My Genetic Library
The Critical Genes I Test For and Why

MTHFR (methylenetetrahydrofolate reductase) converts dietary folate into 5-methyltetrahydrofolate (5-MTHF), the only form of folate that crosses the blood-brain barrier and drives methylation. The C677T variant produces a thermolabile enzyme with up to 70% reduced activity in TT carriers.

C677T is one of the most clinically consequential SNPs in the human genome. Reduced enzyme activity elevates homocysteine, depletes SAMe, and impairs production of neurotransmitters, phospholipids, and glutathione. Synthetic folic acid in fortified foods and supplements can block receptors in these individuals, worsening the bottleneck. This SNP is tested on three different panels because it matters to all three: general healthspan, preconception (neural tube defects, miscarriage), and hormone detox (SAMe drives oestrogen methylation via COMT).

Associated with hyperhomocysteinaemia, cardiovascular disease, migraines, depression, neural tube defects, recurrent miscarriage, male infertility, and increased chemotherapy toxicity. Carriers typically benefit from methylfolate rather than folic acid, alongside B12, B6, and riboflavin co-factors.

The A1298C variant reduces MTHFR activity by roughly 30% but affects a different enzyme domain than C677T. It impacts BH4 (tetrahydrobiopterin) regeneration — the essential cofactor for making dopamine, serotonin, norepinephrine, and nitric oxide.

Compound heterozygosity (one copy of 677 + one copy of 1298) can produce more significant clinical effects than either variant alone. BH4 depletion is increasingly recognised in chronic fatigue, mood dysregulation, and autism-spectrum presentations. For women planning pregnancy, the pairing matters enormously.

More strongly linked to neurotransmitter imbalance, anxiety, insomnia, and chronic pain than to cardiovascular risk. Testing informs targeted support with methylfolate, B12, and BH4-sparing nutrients.

Methionine synthase (MTR) uses vitamin B12 as a cofactor to recycle homocysteine into methionine — the precursor to SAMe, the body's universal methyl donor.

MTR variants increase enzyme activity but simultaneously deplete B12 faster, creating a functional B12 deficiency even with adequate intake. This is often missed on standard serum B12 testing.

Linked to elevated homocysteine, peripheral neuropathy, cognitive impairment, and anaemia. Carriers often need methylcobalamin or hydroxocobalamin supplementation, particularly alongside MTRR variants.

Methionine synthase reductase regenerates oxidised B12 back to its active form so MTR can keep working. Without functional MTRR, B12 becomes trapped in an unusable state.

A66G is extremely common. Combined with MTR variants, it creates a synergistic B12 bottleneck that amplifies homocysteine elevation and methylation dysfunction — a real problem in pregnancy where methyl donors fuel fetal DNA synthesis and neural tube closure.

Associated with neural tube defects, Down syndrome risk, cardiovascular disease, and methylation-related mood symptoms. Carriers benefit from active B12 forms and may need higher doses than reference ranges suggest.

Cystathionine beta-synthase diverts homocysteine down the transsulfuration pathway to produce cysteine, glutathione, taurine, and hydrogen sulfide — critical for detoxification and antioxidant defence.

Upregulating CBS variants can dump sulfur metabolites too quickly, depleting methionine upstream and producing ammonia, excess taurine, and sulfite sensitivity. This manifests as brain fog, sulfur food intolerance, and poor methylation despite adequate folate. GrowBaby tests two CBS variants because CBS activity also influences miscarriage and homocysteine-related pregnancy complications.

Relevant to glutathione status, histamine metabolism, and tolerance of sulfur-containing foods (cruciferous vegetables, alliums, eggs). Careful nutrient sequencing is often required before aggressive methyl-donor supplementation.

MTHFD1 is a trifunctional enzyme that interconverts folate derivatives, supplying the substrates that feed into MTHFR, DNA synthesis, and purine/pyrimidine production.

Variants reduce the pool of usable folate and divert it toward DNA synthesis at the expense of methylation — creating folate "functional deficiency" even with adequate intake.

Strongly associated with neural tube defects, placental abruption, and preterm birth. Preconception and pregnancy are critical windows where MTHFD1 status informs folate form and dose.

Choline dehydrogenase converts choline to betaine, which donates a methyl group to remethylate homocysteine independently of folate — a backup methylation pathway.

Variants reduce this enzyme's activity, making carriers dependent on direct dietary choline (eggs, liver) and betaine (spinach, beets, wheat germ) to maintain methylation balance — particularly important when MTHFR variants are also present.

Elevated risk of fatty liver, neural tube defects, and low-birthweight babies. Choline needs in pregnancy may be substantially higher than the standard 450 mg/day recommendation.

Phosphatidylethanolamine N-methyltransferase uses SAMe to make phosphatidylcholine in the liver — the body's own endogenous source of choline when dietary intake is low.

Variants dramatically reduce endogenous choline synthesis, making dietary choline non-negotiable. Women are more affected than men because oestrogen upregulates PEMT — meaning post-menopausal women and those with PEMT variants face dramatically increased choline requirements.

Strong contributor to non-alcoholic fatty liver disease (NAFLD), cholestasis of pregnancy, and SAM-e depletion. A clear case for eggs, liver, or targeted phosphatidylcholine supplementation.

Transcobalamin II is the transport protein that delivers B12 from blood into cells where it can be used. A broken delivery truck means B12 is circulating but not reaching the enzymes that need it.

Variants produce functional B12 deficiency with normal serum B12 — one of the most commonly missed causes of methylation failure, neuropathy, and cognitive symptoms. MMA (methylmalonic acid) testing is a more accurate marker in carriers.

Relevant to recurrent pregnancy loss, fatigue, peripheral neuropathy, and cognitive symptoms when serum B12 looks "normal". Carriers often need methylcobalamin or hydroxocobalamin in higher doses.

COMT (catechol-O-methyltransferase) sits at the intersection of methylation, neurotransmitter regulation, and hormone detox. See the full entry in Section 09 — Neurotransmitters, Mood & Cognition for the warrior/worrier framework, and Section 11 — Hormone Synthesis & Detoxification for its role in oestrogen methylation. GrowBaby tests four COMT variants because maternal COMT function influences both stress regulation and fetal development.

Apolipoprotein E transports cholesterol and phospholipids between tissues — particularly between the liver, bloodstream, and brain. Three major isoforms exist (E2, E3, E4), produced by combinations of two SNPs. The E4 allele is the strongest known genetic risk factor for late-onset Alzheimer's disease and accelerated cardiovascular disease.

APOE status fundamentally shifts dietary strategy. E4 carriers respond poorly to saturated fat and show blunted response to alcohol. E2 carriers have lower LDL but elevated triglyceride risk and type III hyperlipidaemia susceptibility. One test, lifelong implications. GrowBaby includes it because APOE4 in mothers is linked to preterm birth and miscarriage, and fetal APOE4 affects placental lipid transfer.

E4 carriers benefit from Mediterranean-style low-saturated-fat diets, aerobic exercise, DHA-rich omega-3s (target ≥8% omega-3 index), tight glucose control, and avoidance of head trauma. Critically, E4 carriers should prioritise deep sleep architecture — the glymphatic system clears amyloid-β from the brain almost exclusively during slow-wave sleep, and E4 carriers accumulate Aβ faster. Seven to nine hours of quality sleep, consistent sleep-wake timing, and interventions like magnesium glycinate, glycine, and evening light restriction become neuroprotective strategies rather than lifestyle luxuries. E2 carriers enjoy a beneficial advantage: enhanced lipid clearance, lower LDL, and association with exceptional longevity — though they should monitor triglycerides and be aware of type III hyperlipidaemia susceptibility. E3/E3 — the most common genotype — carries baseline population risk.

Lipoprotein lipase breaks down triglyceride-rich lipoproteins (chylomicrons, VLDL) on blood vessel walls, releasing fatty acids for tissue use. It's the rate-limiting step in dietary fat clearance.

Variants alter post-meal triglyceride spikes, HDL cholesterol, and the cardiovascular response to dietary fat composition. The same meal produces very different lipid panels in different LPL genotypes.

Informs decisions about dietary fat ratios, aerobic exercise intensity (a potent LPL inducer), and omega-3 dosing for triglyceride management. This is the gene that determines whether a high-fat meal leaves you energised or sluggish — and whether your post-meal triglyceride spike is a blip or a cardiovascular event in slow motion.

Cholesteryl ester transfer protein shuttles cholesterol esters between HDL and LDL/VLDL. Lower CETP activity produces larger, more protective HDL particles and has been linked to exceptional longevity.

CETP genotype modifies the cardiovascular benefit of alcohol, exercise, and statin therapy. It's a key marker for understanding why some clients respond dramatically to lifestyle changes while others plateau.

Helps personalise HDL-raising strategies and contextualise LDL targets alongside particle size and inflammation markers. The AA genotype is a beneficial variant — associated with higher HDL, larger protective HDL particles, and exceptional longevity in centenarian studies. One of the genuinely "good news" results a client can receive.

Apolipoprotein C-III inhibits lipoprotein lipase and hepatic uptake of triglyceride-rich particles. Higher levels mean slower triglyceride clearance and more vascular inflammation.

APOC3 variants significantly modify fasting and postprandial triglyceride levels and the response to dietary carbohydrate load.

Informs carbohydrate tolerance, fat-timing strategies, and the aggressiveness of triglyceride targets. Carriers with high-activity APOC3 often do poorly on high-carb, low-fat diets — the carbohydrate load drives triglycerides up without effective clearance. These are the clients who genuinely thrive on lower-carb Mediterranean or modified keto approaches. Loss-of-function variants are associated with protection against coronary disease.

Paraoxonase-1 rides on HDL particles and hydrolyses oxidised lipids, preventing LDL oxidation — the initiating event in atherosclerosis. It also detoxifies organophosphate pesticides and certain nerve agents.

PON1 activity varies up to 40-fold between individuals. Low activity carriers face greater cardiovascular risk from oxidative stress and greater toxicity from conventional agricultural exposures.

Argument for organic produce, antioxidant-rich diets, and polyphenol-dense foods (pomegranate, olive oil) which directly upregulate PON1.

Endothelial nitric oxide synthase produces nitric oxide — the molecule that relaxes blood vessels, controls blood pressure, and regulates platelet function. It is also critical for exercise response and erectile function.

Reduced eNOS activity is linked to hypertension, endothelial dysfunction, pre-eclampsia, and impaired exercise adaptation.

Informs strategies using dietary nitrates (beetroot, leafy greens), L-arginine/citrulline, BH4-supporting nutrients, and aerobic exercise — all of which augment nitric oxide production.

Angiotensin-converting enzyme controls blood pressure by converting angiotensin I to angiotensin II, a potent vasoconstrictor. The I/D polymorphism affects circulating ACE levels by up to 50%.

DD genotype is associated with higher ACE activity, greater salt sensitivity, hypertension risk, and power/strength athletic performance. II genotype favours endurance performance and lower blood pressure.

Directly informs salt intake, potassium strategy, exercise prescription (strength vs endurance bias), and medication response to ACE inhibitors.

Angiotensinogen is the precursor protein in the renin-angiotensin system. Variants raise circulating angiotensinogen levels, amplifying the hypertensive cascade.

AGT variants are one of the clearest genetic predictors of salt-sensitive hypertension and response to DASH-style dietary patterns.

Strong indicator for aggressive sodium moderation, potassium-rich intake, and blood pressure monitoring earlier in life than conventional guidelines suggest.

The aryl hydrocarbon receptor senses environmental toxins (dioxins, PAHs, cigarette smoke) and switches on Phase I detox genes including CYP1A1, CYP1A2, and CYP1B1. It is also central to immune regulation and placental function.

Variants alter how responsively AhR turns on Phase I — potentially causing rapid activation of procarcinogens before Phase II can catch up. In pregnancy, AhR dysregulation is linked to placental insufficiency and preterm birth.

Reinforces the importance of cruciferous vegetables (which modulate AhR gently), reducing char-grilled and smoked food intake, and minimising environmental toxin burden in preconception.

CYP1A1 metabolises polycyclic aromatic hydrocarbons (charred food, tobacco smoke, diesel exhaust) and hydroxylates oestrogen into either protective 2-OH or potentially carcinogenic 4-OH metabolites.

Variants create a rapid Phase I enzyme that can outpace Phase II conjugation, producing a backlog of reactive intermediates that damage DNA. Tested on three panels because it matters for general healthspan, pregnancy (placental toxin clearance), and oestrogen-sensitive tissue risk (breast, endometrium, prostate).

Elevated risk of hormone-sensitive cancers, particularly in combination with smoking, char-grilled meats, or poor cruciferous vegetable intake. DIM, sulforaphane, and I3C from brassicas are central interventions.

This variant alters the enzyme's active site, changing which compounds it prefers to metabolise and how quickly.

Combined with Msp1 variants, it compounds the risk of oxidative DNA damage from activated metabolites.

Informs strategies to keep Phase I and Phase II in balance: brassica intake, antioxidant status, and reduction of char-grilled and smoked foods.

CYP1A2 handles roughly 95% of caffeine metabolism and clears heterocyclic amines from well-done meats, certain medications, and melatonin.

"Slow metabolisers" clear caffeine up to 4 times more slowly than fast metabolisers. In slow metabolisers, more than 2 cups of coffee daily is associated with increased myocardial infarction risk; in fast metabolisers, coffee is cardioprotective. In pregnancy, slow caffeine metabolism raises risk of low birthweight.

The single clearest example of why "coffee is good for you" is wrong without genetic context. Also informs sleep architecture, anxiety sensitivity, and safe caffeine timing in pregnancy.

CYP1B1 catalyses the 4-hydroxylation of oestrone and oestradiol — producing the most proliferative oestrogen metabolite, 4-OH-E1/E2, which can convert to DNA-damaging quinones. This is the oestrogen pathway you want to keep quiet.

Variants upregulate CYP1B1, shifting oestrogen flow away from the protective 2-OH pathway and toward the carcinogenic 4-OH pathway. Strongly linked to earlier menopause, heavier hot flushes, and oestrogen-sensitive cancers (breast, endometrial).

Carriers benefit from DIM, sulforaphane, I3C, resveratrol, genistein, and daidzein — all CYP1B1 inhibitors — alongside avoiding smoking, managing weight and inflammation.

CYP3A4 is the most abundant cytochrome P450 enzyme in humans, handling up to 60% of liver P450 activity. It metabolises testosterone, oestrogen, cortisol, and approximately 50% of prescription medications.

Variants affect hormone clearance rate, the 16-OH oestrogen metabolite ratio, and drug dosing decisions — particularly relevant for HRT, statins, calcium channel blockers, and benzodiazepines.

Informs grapefruit avoidance (a potent CYP3A4 inhibitor), medication dose adjustment, and oestrogen detox strategy. This is pharmacogenomic territory that crosses into the Medcheck panel.

CYP2R1 performs the liver's 25-hydroxylation step converting vitamin D3 into 25(OH)D — the form measured in blood tests.

Variants reduce activation efficiency, meaning carriers need substantially higher intake to achieve the same 25(OH)D blood level. Often the missing explanation for clients who "don't respond" to standard vitamin D supplementation.

Guides personalised vitamin D dosing alongside VDR and GC genetics, rather than relying on generic 1000-2000 IU recommendations.

Glutathione S-transferase Mu-1 conjugates glutathione onto heavy metals, carcinogens, oxidised lipids, reactive Phase I metabolites, and oestrogen quinones for safe excretion.

Approximately 50% of the population is born without this gene entirely (full deletion). These individuals rely more heavily on other GST isoforms and have reduced capacity to detoxify mercury, cadmium, pesticides, and reactive oestrogen metabolites.

Deletion genotype raises risk for hormone-sensitive cancers, chemical sensitivity, and complications during chemotherapy. Emphasis on sulforaphane, NAC, glycine, and minimising toxic burden.

GSTP1 is highly expressed in the lungs, brain, placenta, and skin — protecting tissues especially vulnerable to oxidative stress.

Variants reduce enzyme affinity for certain substrates, lowering protection against tobacco smoke, air pollution, neurotoxins, and UV-induced skin damage. DNA Skin includes this because poor GSTP1 activity in skin tissue means more oxidative skin ageing and sensitivity.

Linked to asthma severity, childhood cancers, neurodegenerative risk, poor chemotherapy outcomes, and impaired skin barrier. Environmental air quality, skin protection, and cruciferous intake become clinically meaningful.

GSTT1 conjugates smaller xenobiotics including solvents, halogenated hydrocarbons, ethylene oxide, certain anaesthetic metabolites, and oestrogen quinones.

Around 20% of people carry full deletions of this gene. Combined with a GSTM1 deletion, detoxification capacity is dramatically compromised.

Higher risk in occupational chemical exposures (salons, healthcare, industrial work), adverse anaesthetic reactions, bladder/colon cancer susceptibility, and — in combination with metabolic syndrome — prostate cancer.

Glutathione S-transferase Alpha-1 is particularly active in the liver and gastrointestinal tract, conjugating steroid hormones, acrylamide (from fried starches), and certain chemotherapy agents.

Variants reduce enzyme expression and matter most in pregnancy, where reduced clearance of steroid hormones and dietary acrylamide (crisps, fries, toast) can affect fetal development.

Argues for avoidance of acrylamide-producing cooking methods (high-heat frying, browning starches), particularly during preconception and pregnancy.

NAD(P)H quinone dehydrogenase-1 neutralises quinones from tobacco smoke, air pollution, benzene, and oestrogen quinone metabolites, and regenerates the reduced forms of CoQ10 and vitamin E.

TT homozygotes have virtually no NQO1 activity, dramatically increasing susceptibility to benzene toxicity, leukaemia, oestrogen-driven breast cancer, and certain solid tumours. It also affects chemotherapy drug activation.

Critical for anyone in high-exposure environments (smokers, firefighters, mechanics, urban commuters), clients using HRT, and clients with a history of oestrogen-sensitive conditions. Informs CoQ10 supplementation strategy and cancer risk modelling.

Epoxide hydrolase converts reactive epoxides from aromatic hydrocarbons (smoke, chemical cleaners, certain plastics) into less reactive diols that can be conjugated and excreted.

Variants reduce enzyme activity, increasing oxidative stress at the skin barrier and raising sensitivity to environmental pollutants.

Particularly relevant to skin sensitivity, fragrance reactions, and accelerated skin ageing from urban air pollution.

Sulfotransferase 1A1 sulfates the 2-, 4-, and 16-OH oestrogen metabolites, rendering them water-soluble for excretion. Sulfated oestrogens also act as a storage pool that can be reactivated by gut sulfatases.

Variants reduce sulfation efficiency, allowing more reactive oestrogen metabolites to circulate. Also affects bioactivation of heterocyclic amines from high-heat cooked meat.

Relevant for anyone on HRT, oral contraceptives, or with oestrogen-dominant conditions. Supports gut microbiome health to manage the deconjugation-reactivation cycle.

UDP-glucuronosyltransferase 2B15 glucuronidates testosterone, dihydrotestosterone (DHT), and the potent DHT metabolite 3α-androstanediol, readying them for excretion. It also processes ethanol and flavonoids.

The TG genotype slows clearance, raising circulating DHT and 3α-diol-17G levels — linked to prostate cancer risk in men and androgen excess symptoms (acne, hair loss, hirsutism) in women.

Particularly important for men considering TRT and women with PCOS or androgen-driven hair loss. Supports sulforaphane, lycopene-rich foods, and weight management.

UGT2B17 is the primary enzyme clearing testosterone, DHT, androsterone, and 3α-androstanediol. Deletion of this gene dramatically raises systemic androgen levels and lowers the urinary T/E ratio — important in anti-doping testing.

Deletion is associated with increased prostate cancer risk in men but protective effects against osteoporosis in postmenopausal women (higher androgen levels support bone mineral density). Rare example of a deletion cutting both ways.

Reshapes decisions around TRT monitoring, prostate screening frequency, HRT composition in post-menopausal women, and androgen-modifying supplements.

Interleukin-6 drives acute-phase responses, fever, CRP production, and chronic inflammatory signalling. Elevated IL-6 is one of the strongest predictors of all-cause mortality in longitudinal studies.

The G allele at -174 is associated with higher IL-6 production, greater CRP, and increased risk of cardiovascular events, Alzheimer's disease, depression, frailty, skin inflammation, and pregnancy-induced hypertension. GrowBaby tests five IL-6 SNPs because maternal inflammation directly affects placental function and fetal neurodevelopment.

High-producer genotypes are the classic indication for ≥8% omega-3 index in cell membranes, polyphenol density, resistance training, and sleep protection — all proven IL-6 suppressors.

The IL-6 receptor translates the IL-6 signal into cellular action. Variants modify how strongly the receptor binds IL-6 and how amplified the downstream inflammatory response is.

Testing IL-6 alongside IL-6R gives a full picture of the signalling axis. Variants are linked to chronic low-grade skin inflammation, post-inflammatory hyperpigmentation, and sensitivity.

Particularly relevant to skin concerns: acne, rosacea, eczema, and persistent redness. Reinforces anti-inflammatory nutrition and topical strategies.

Tumour necrosis factor alpha drives acute inflammation, insulin resistance, cartilage breakdown, and autoimmune tissue damage.

The A allele at -308 is a high-producer variant linked to increased risk of rheumatoid arthritis, psoriasis, inflammatory bowel disease, metabolic syndrome, depression, and skin sensitivity.

High-producer status argues for anti-inflammatory dietary patterns (Mediterranean, whole-food plant-forward), tight glycaemic control, and visceral fat reduction — adipose tissue is a major TNF-α source.

Interleukin-1 alpha triggers local inflammatory cascades, particularly at epithelial barriers — gums, gut lining, skin.

Variants are well-established risk factors for severe periodontal disease, which is itself linked to cardiovascular events, dementia, and systemic inflammation.

Justifies aggressive oral hygiene, CoQ10 and vitamin C support for gum tissue, and barrier-supporting nutrients (zinc, glutamine, omega-3s).

The -889 variant sits in the promoter region and affects how readily the IL-1A gene is transcribed, modifying cytokine production levels.

Combined with 4845, it sharpens risk assessment for chronic inflammatory conditions at mucosal and epithelial surfaces.

Relevant for clients with recurrent gum disease, eczema, IBD-spectrum symptoms, or chronic sinusitis.

Interleukin-1 beta drives fever, pain sensitisation, sickness behaviour, and chronic inflammatory signalling throughout the body.

The T allele increases IL-1B production and is associated with gastric cancer risk (especially with H. pylori), Alzheimer's disease, and chronic pain syndromes.

Reinforces the importance of H. pylori screening, gut microbiome care, and sustained anti-inflammatory nutrition.

The -511 variant modifies IL-1B transcription rate and is particularly relevant when combined with 3954 for comprehensive risk stratification.

Refines inflammation phenotyping and informs whether a client runs hot or cool at baseline.

Contributes to total "inflammatory load" scoring alongside other cytokine variants, guiding intervention intensity.

IL-1 receptor antagonist is the body's endogenous inhibitor of IL-1 signalling — the "brake" on the IL-1 system.

Variants reducing IL-1RN activity leave IL-1 inflammation unopposed, accelerating chronic inflammatory conditions.

Must be interpreted alongside IL-1A and IL-1B variants to understand net inflammatory tone. Anti-inflammatory nutrition becomes clinically urgent rather than optional.

C-reactive protein is the acute-phase protein whose blood level (hs-CRP) is routinely used to assess cardiovascular and inflammatory risk.

CRP gene variants shift baseline production, meaning identical hs-CRP readings carry different clinical weight in different people. It also means some clients appear "low inflammation" on testing while still running high cytokine activity elsewhere.

Contextualises hs-CRP results and refines cardiovascular risk prediction. High-producer carriers warrant earlier lipid and glucose optimisation, plus proactive skin sensitivity support.

Human leukocyte antigen DQ2 and DQ8 haplotypes present gluten-derived peptides to T-cells. Without one of these haplotypes, coeliac disease is virtually impossible.

Around 30-40% of the population carry DQ2 or DQ8 but only 1% develop coeliac disease — meaning genetics identifies the at-risk population but environmental triggers decide outcome. Importantly, a negative result rules coeliac disease out for life.

Carriers benefit from vigilance, particularly during life stressors, infections, and pregnancy. It also informs decisions about dairy, grains, and non-coeliac gluten sensitivity management.

This gene regulates the amount of water lost through the skin's outer layers. Variants produce an intrinsically leaky barrier, allowing irritants in and moisture out.

Explains lifelong patterns of dry, reactive, easily-inflamed skin despite good skincare. Combined with inflammation variants, it defines the "sensitive skin" phenotype biologically.

Informs topical lipid complexes (ceramides, phospholipids, fatty acids), avoidance of foaming cleansers and harsh exfoliants, and anti-inflammatory dietary patterns.

Manganese superoxide dismutase converts superoxide radicals inside mitochondria into hydrogen peroxide, which is then cleared by catalase and glutathione peroxidase.

The Ala16 variant reduces transport of SOD2 into mitochondria, impairing the first line of antioxidant defence. Associated with cardiomyopathy, hypertension, diabetes complications, breast cancer risk (particularly with HRT or smoking), and accelerated skin ageing.

Ala16 carriers benefit from manganese-rich foods, polyphenol-dense intake (particularly from pomegranate, berries, green tea), and exercise-induced antioxidant adaptation — but also need attention to recovery. Val/Val carriers carry the beneficial wild-type — efficient mitochondrial SOD2 import and robust endogenous antioxidant defence.

Catalase decomposes hydrogen peroxide into water and oxygen — a critical step to prevent the formation of highly damaging hydroxyl radicals.

Low-activity variants leave hydrogen peroxide to accumulate, particularly stressing hair follicles (premature greying), liver, and vascular endothelium.

Relevant in hypertension, diabetes, and vitiligo susceptibility. Informs iron and copper status (co-factors) and the use of exogenous antioxidants vs hormesis-driving interventions like sauna and fasting.

Glutathione peroxidase-1 uses selenium to clear hydrogen peroxide and lipid peroxides, partnering with glutathione to protect cell membranes.

The Leu198 variant reduces GPX1 activity and its response to selenium supplementation, linked to breast, lung, and bladder cancer risk.

Selenium status becomes clinically meaningful — 2 Brazil nuts daily or a targeted 100-200 mcg supplement alongside glutathione precursors (NAC, glycine). Pro/Pro carriers have the beneficial genotype — full GPX1 activity and strong selenium responsiveness, providing robust peroxide clearance. Also informs thyroid health, as selenium is central to thyroid hormone conversion.

The vitamin D receptor binds active vitamin D and translocates to the nucleus to regulate ~2000 genes. Fok1 alters the receptor's starting codon, producing a longer or shorter receptor protein.

Variants reduce receptor sensitivity, meaning two people with identical blood 25(OH)D levels can have markedly different biological vitamin D action. In pregnancy, VDR variants are linked to preterm birth and small-for-gestational-age outcomes.

Linked to bone density, immune regulation, and autoimmunity (MS, Hashimoto's, IBD). Informs target 25(OH)D levels — many carriers need upper-quartile levels to achieve functional sufficiency.

Bsm1 is an intronic variant strongly linked to VDR mRNA stability, calcium absorption efficiency, and bone mineral density.

Variants affect peak bone mass in youth and osteoporosis risk in later life, and they modify response to calcium and vitamin D supplementation.

Informs strategies for resistance training load, calcium partitioning (getting calcium into bone rather than arteries), and vitamin K2 MK-7 supplementation.

Taq1 is in linkage disequilibrium with Bsm1, meaning the two variants tend to travel together and produce compound effects on VDR function.

Reading Taq1 alongside Bsm1 and Fok1 generates a complete VDR activity signature rather than a single-variant snapshot.

Combined VDR genotype is one of the strongest predictors of autoimmune disease risk, osteoporosis, and personalised vitamin D targets.

COL1A1 codes for the alpha-1 chain of type I collagen — the structural protein making up 90% of bone matrix and the bulk of tendons, ligaments, and skin.

The Sp1 variant alters collagen quality and the ratio of collagen chains, weakening bone independently of mineral density and reducing skin firmness. It's a well-validated osteoporotic fracture predictor, particularly in postmenopausal women. DNA Skin includes it because reduced collagen quality accelerates visible ageing, laxity, and poor wound healing.

Informs urgency around weight-bearing exercise, protein intake timing, vitamin C (collagen cofactor), silicon, hydrolysed marine collagen supplementation, and resistance training beginning in midlife rather than later.

Matrix metalloproteinase-1 breaks down existing collagen. Upregulated by UV exposure, inflammation, and glycation, it is the enzyme responsible for wrinkle formation.

The 2G allele produces higher MMP1 activity — meaning collagen is broken down faster than new collagen can replace it. Combined with a COL1A1 variant (reduced quality production), it's a double hit.

Clear case for mineral sunscreens (zinc oxide, titanium dioxide), topical MMP1 inhibitors (calendula, rooibos aspalathin), antioxidant-dense skincare, and aggressive sun protection in carriers.

Group-specific component (GC) protein is the main carrier of vitamin D in blood, ferrying it to tissues and to the kidney for final activation.

Variants change binding affinity and circulating 25(OH)D levels, meaning blood test values can be misleading: some carriers look "sufficient" while tissue delivery is poor.

Combined with VDR and CYP2R1, GC completes the picture of individual vitamin D metabolism and informs personalised dosing rather than population-average recommendations.

Beta-carotene oxygenase 1 cleaves dietary beta-carotene from plant foods into retinal, the active precursor of vitamin A.

Poor converters (up to 45% of the population) can show clinical signs of vitamin A deficiency despite abundant intake of orange and green vegetables. This is often invisible without genetic testing.

Affects immune function, skin integrity, night vision, thyroid health, and — in pregnancy — fetal development. Poor converters benefit from preformed retinol sources (pasture-raised liver, egg yolks, dairy, cod liver oil) rather than relying on carotenoids alone.

Fatty acid desaturase-1 is the enzyme that converts plant-derived ALA and LA into the long-chain fatty acids the body actually uses: EPA, DHA, and arachidonic acid.

Poor converters (particularly TT at rs174537) get only 1-5% conversion of ALA into EPA/DHA, meaning plant-based omega-3 sources (flax, chia, walnuts) are nearly useless at raising tissue levels.

One of the clearest cases for preformed EPA/DHA from fish or algae oil, particularly in pregnancy, cognitive decline prevention, and inflammatory conditions. Informs testing the omega-3 index directly (target ≥8%).

The HFE protein regulates iron absorption via hepcidin signalling. The C282Y variant impairs this regulation, allowing iron to accumulate unchecked in the liver, heart, pancreas, and joints.

C282Y homozygosity is the most common cause of hereditary haemochromatosis in people of Northern European descent. Untreated iron overload leads to cirrhosis, diabetes, cardiomyopathy, and joint destruction — all preventable with early detection. H63D is milder but produces compound heterozygous risk with C282Y.

One of the highest-value genetic tests in existence for at-risk populations. Informs iron intake, vitamin C timing (which increases iron absorption), and the need for ferritin monitoring. Also linked to neurodegenerative risk via brain iron accumulation.

FUT2 determines "secretor status" — whether you secrete ABO blood group antigens into saliva, mucus, and gut lining. This shapes the gut microbiome, influences B12 absorption, and affects susceptibility to norovirus and certain infections.

Non-secretors (AA at Gly258Ser) tend to have lower serum B12, reduced bifidobacterium populations, and greater Crohn's disease risk — but are paradoxically resistant to norovirus and some rotaviruses.

Informs B12 testing and supplementation strategy, prebiotic selection (particularly bifidogenic fibres), and risk stratification for inflammatory bowel disease.

Peroxisome proliferator-activated receptor gamma controls adipocyte differentiation, insulin sensitivity, and the response of fat tissue to dietary fat composition.

The Ala12 variant is protective against type 2 diabetes but more sensitive to dietary fat quality — Ala12 carriers gain weight on saturated fat but lean out on monounsaturated and omega-3 rich diets.

One of the clearest gene-diet interactions known. Ala12 carriers do well on avocado, olive oil, nuts, and fatty fish but gain weight on butter, cream, and coconut oil. Pro12 carriers tolerate saturated fat better. This is the gene that settles the "is coconut oil healthy?" debate — it depends on your PPARG. Informs precise fat composition prescriptions rather than blanket low-fat or high-fat advice.

Transcription factor 7-like 2 regulates pancreatic beta-cell function, insulin secretion, and incretin response after meals.

The T allele is associated with impaired insulin secretion and is the strongest common genetic predictor of type 2 diabetes (TT genotype carries roughly double the risk). It also modifies response to metformin and lifestyle interventions.

Justifies aggressive lifestyle prevention decades before blood sugar becomes abnormal. In practical terms: protein and fat before carbs at every meal, low-glycaemic carb sources (sweet potato over white rice, steel-cut oats over instant), a 10-minute walk after eating, and resistance training to maintain insulin sensitivity. TT carriers who eat a standard Western carb-heavy breakfast are fighting their biology before 9am.

GLUT2 is the glucose transporter in the liver, pancreas, and brain. It also senses dietary sugar and shapes subjective preference for sweet foods.

Variants are linked to higher habitual sugar intake, suggesting genetic drive rather than willpower failure in some clients with sugar cravings.

Reframes sugar cravings as a biological phenotype, not a willpower failure. Practical food strategies: start every meal with 30g protein (eggs, Greek yoghurt, meat, fish), add cinnamon to coffee and oats, keep chromium-rich foods regular (broccoli, grass-fed beef, turkey), and redesign the kitchen environment to reduce cue exposure. The craving is real — the gene confirms it.

FTO influences hypothalamic appetite signalling, satiety, and ghrelin suppression after meals. It's one of the strongest common genetic contributors to body weight.

The A allele is associated with higher calorie intake, poorer satiety, and increased BMI — but the effect is entirely offset by regular physical activity. Genetics is not destiny here; it's a lever.

Clear case for protein-forward meals — 30-40g protein at breakfast (which directly overrides FTO's impaired satiety signalling), structured meal timing rather than grazing, and fibre-rich whole foods that slow gastric emptying. FTO carriers who eat a high-protein breakfast report the same fullness as non-carriers by mid-morning. The gene also responds dramatically to exercise: the BMI effect is entirely offset by regular physical activity. Reassures carriers that food and movement strategy still works — arguably more powerfully than for non-carriers.

Ectonucleotide pyrophosphatase/phosphodiesterase 1 inhibits insulin receptor signalling. Variants increase inhibition, impairing the cell's ability to hear the insulin signal.

Variants are linked to insulin resistance, gestational diabetes, and childhood obesity. In pregnancy, identifying this early allows dietary and lifestyle intervention before glucose intolerance develops.

Argues for proactive glucose management in pregnancy: protein-forward meals, post-meal walking, and targeted monitoring.

Glucokinase is the pancreatic beta-cell's glucose sensor, triggering insulin release when blood sugar rises. It also controls liver glycogen storage.

Variants alter the glucose threshold for insulin release, producing a higher fasting glucose set-point and increased gestational diabetes risk.

Informs gestational diabetes monitoring and may explain "unexplained" mild fasting hyperglycaemia in pregnancy.

Insulin-like growth factor 2 mRNA binding protein 2 regulates insulin secretion and fetal growth signalling.

One of the top replicated type 2 diabetes risk genes. In pregnancy, variants influence gestational diabetes risk and birthweight regulation.

Combined with GCK, ENNP1, and SLC30A8 variants, builds a comprehensive gestational diabetes risk profile for preconception planning.

Solute carrier family 30 member 8 transports zinc into pancreatic beta-cell granules, where zinc is essential for insulin crystallisation and secretion.

Variants impair zinc delivery and insulin secretion efficiency, contributing to type 2 diabetes and gestational diabetes risk. Clients may have functional zinc deficiency despite adequate dietary intake.

Argues for attention to zinc status, especially in pregnancy, alongside overall insulin-supportive strategies.

The melatonin receptor 1B mediates melatonin's effects on sleep onset, circadian rhythm, and pancreatic insulin secretion — melatonin normally inhibits insulin at night.

Variants blunt melatonin's normal suppression of overnight insulin, raising fasting glucose and gestational diabetes risk. They are also associated with large-for-gestational-age birthweight.

Carriers benefit from magnesium, chamomile, caffeine elimination, and attention to circadian rhythm protection (consistent sleep-wake times, morning light exposure, dim evenings).

TAS2R38 is the primary receptor for bitter compounds in cruciferous vegetables (PTC/PROP sensitivity). Super-tasters experience broccoli, kale, and Brussels sprouts as intensely bitter.

Taster status explains long-standing dietary aversions and cruciferous avoidance — a problem when these foods are central to oestrogen detoxification and Phase II support. Three SNPs together define the complete PAV (taster) vs AVI (non-taster) haplotype.

Super-tasters benefit from specific cooking techniques: roasting Brussels sprouts with olive oil and salt (Maillard reaction masks bitterness), fermenting cabbage into sauerkraut or kimchi, blending kale into smoothies with banana and nut butter, or pairing broccoli with cheese sauce and garlic. When all else fails, broccoli sprout extract or DIM capsules deliver sulforaphane without the taste battle. Also linked to lower colon cancer risk (when cruciferous intake is overcome) and reduced alcohol preference.

Aldehyde dehydrogenase-2 clears acetaldehyde — the toxic intermediate of alcohol metabolism and a known Group 1 human carcinogen.

The A allele dramatically reduces ALDH2 activity, causing acetaldehyde accumulation, facial flushing, and markedly elevated risks of oesophageal, head and neck, and gastric cancers when drinking. Very common in East Asian populations.

One of the most actionable genetic results: carriers benefit from significantly reduced or eliminated alcohol intake. Beyond alcohol, ALDH2 also clears aldehydes from fried foods, smoked meats, overripe fruit, and urban air pollution — meaning carriers may also benefit from gentler cooking methods (steaming, poaching, slow-cooking) and reduced char-grilled and deep-fried food intake.

MCM6 sits upstream of the lactase gene and controls whether lactase production continues past childhood. The T allele confers lactase persistence.

CC genotype indicates lactose intolerance with high specificity. Informs whether dairy symptoms are lactose-driven, casein-driven (A1 vs A2), or histamine-driven — a common source of diagnostic confusion.

Directs dietary strategy with precision: CC genotypes can typically tolerate hard aged cheeses (Parmesan, aged cheddar), full-fat Greek yoghurt, kefir, and butter where lactose is minimal, but react to milk, ice cream, and soft cheeses. A2 dairy (from A2-certified herds or goat/sheep milk) may be tolerated when standard cow dairy is not. Separates the lactose question from the casein question from the histamine question — three different mechanisms clients often conflate.

Catechol-O-methyltransferase breaks down dopamine, norepinephrine, and catecholoestrogens — particularly in the prefrontal cortex and in oestrogen methylation. Activity varies 3-4 fold between Val/Val ("warriors") and Met/Met ("worriers").

Met/Met carriers have higher baseline dopamine and better working memory under calm conditions but crash under acute stress. Val/Val carriers clear dopamine fast, thrive under pressure, but may struggle with sustained focus and be more prone to addiction-seeking behaviour. The same variant also controls how well you clear methylated oestrogens — slow metabolisers accumulate oestrogen metabolites linked to breast cancer risk.

Informs stress management strategy, caffeine tolerance, response to nootropics, oestrogen detoxification capacity, and the clinical picture of ADHD, anxiety, obsessive traits, PMS, and menopause symptoms. Slow metabolisers can become overstimulated on aggressive methyl-donor protocols. Val/Met heterozygotes may carry a beneficial balance — moderate dopamine clearance that supports both focus under pressure and cognitive flexibility under calm conditions.

Monoamine oxidase A breaks down serotonin, dopamine, and norepinephrine in the brain and gut. It's the target of old-school MAOI antidepressants.

Variants shift the speed of neurotransmitter turnover, affecting stress resilience, PMS, postpartum mood, and vulnerability to depression in pregnancy — a window where hormonal shifts already stress monoamine regulation.

Informs pregnancy and postpartum mental health planning, tyrosine/tryptophan balance, and caution with tyramine-containing foods in slow metabolisers.

BDNF is the brain's primary "fertiliser" — it drives neuron survival, synaptic plasticity, long-term memory formation, and adult neurogenesis, especially in the hippocampus.

The Met66 variant reduces activity-dependent BDNF secretion, affecting memory consolidation, depression risk, exercise response to cognition, and recovery from traumatic brain injury. In pregnancy, maternal BDNF levels drop in the third trimester — Met carriers need proactive support.

Met carriers benefit disproportionately from aerobic exercise, omega-3 DHA, sauna, and intermittent fasting, all of which upregulate BDNF. Val/Val carriers enjoy a beneficial genotype — full activity-dependent BDNF secretion, robust neuroplasticity, and greater resilience to cognitive decline and mood disorders. Also informs urgency of learning-demanding stimulation across the lifespan.

The serotonin transporter clears serotonin from synapses — it is the target of SSRI antidepressants. Variants change transporter density and serotonin signalling dynamics.

The "short" variant is linked to greater amygdala reactivity, increased depression risk under life stress, but also greater positive response to supportive environments — a classic example of gene-environment interaction, not a simple risk allele.

Argues for protective environment, tryptophan-containing foods, omega-3s, vitamin D, and meaningful relationship investment. Also informs SSRI response and nuance in trauma-informed care.

The 5-HT1A receptor is a key autoreceptor regulating serotonin release. The G allele increases receptor expression, dampening serotonin output.

G/G carriers show increased risk of depression, anxiety, and suicidality, and often respond poorly to SSRIs alone.

Relevant for personalised mental health strategy including nutrient co-factors (vitamin D, B6, zinc), movement, and the integration of trauma-informed therapy alongside pharmacology.

FKBP5 regulates glucocorticoid receptor sensitivity and the HPA axis recovery after stress. It is a key mediator of how early-life adversity becomes biologically embedded.

Risk variants amplify the biological impact of childhood trauma, increasing lifetime risk of PTSD, depression, and cardiovascular disease — but respond strongly to trauma-informed intervention and epigenetic modification.

FKBP5 risk carriers benefit from evidence-based trauma-processing therapies: working with a licensed EMDR (Eye Movement Desensitisation and Reprocessing) therapist is particularly well-supported for PTSD and complex trauma, as EMDR directly targets the reconsolidation of traumatic memories that FKBP5 variants make biologically "stickier." EFT tapping (Emotional Freedom Techniques), somatic experiencing, brainspotting, and neurofeedback are additional modalities shown to downregulate HPA axis hyperactivity. Nutritional support for cortisol regulation (phosphatidylserine, ashwagandha, magnesium, omega-3s), sleep prioritisation, nervous system regulation practices (vagal toning, breathwork), and boundary work all complement the therapeutic process. The key clinical insight is that FKBP5 carriers may need more intensive and sustained follow-up after trauma exposure than non-carriers — the biology demands it, and knowing that reframes the need for professional support as a physiological requirement, not a personal weakness.

The oxytocin receptor mediates social bonding, empathy, trust, maternal behaviour, and recovery from social stress.

OXTR genotype shapes what some practitioners call the "empath vs stoic" phenotype. GG carriers tend toward the empath end — high empathic accuracy, deep social attunement, and strong oxytocin-driven bonding. AA carriers lean toward the stoic end — reduced sensitivity to social cues, higher stress reactivity to rejection, but often greater emotional self-sufficiency. Neither is better; they're different operating systems with different needs.

Stoic-phenotype (AA) carriers may need more intentional investment in social connection, physical touch, parasympathetic tone work, and the therapeutic relationship itself as a biochemical intervention. Empath-phenotype (GG) carriers carry a beneficial variant — associated with greater empathic accuracy, stronger social bonding, and more resilient stress recovery through social support, though they may also be more vulnerable to compassion fatigue and emotional absorption. This is one of the variants where seeing a "beneficial" result is genuinely reassuring.

AKT1 sits downstream of dopamine D2 signalling. Variants influence how cannabis use interacts with psychosis and cognitive impairment risk.

CC carriers who use cannabis show ~7-fold increased risk of psychosis compared to non-users with the same genotype. A clinically meaningful signal, particularly in adolescents.

One of the most actionable cannabis-related genetic results, particularly relevant now that cannabis is legalised in many regions. Informs a clear avoidance rationale.

Glycogen synthase kinase 3 beta is a core target of lithium and a node in bipolar and depression biology. It regulates neuroplasticity, circadian rhythm, and inflammation.

Three GSK3B variants together profile susceptibility to mood episodes and response to mood-stabilising treatments and low-dose lithium orotate strategies.

Informs nutritional mood support, particularly inositol, omega-3 EPA, low-dose lithium orotate, and circadian rhythm protection.

Ankyrin-3 anchors ion channels at the axon initial segment, controlling the firing threshold and rhythm of neurons.

ANK3 variants are among the most replicated genetic risk factors for bipolar disorder and influence response to lithium and other mood stabilisers.

Informs the importance of sleep regularity, circadian rhythm protection, and caution with stimulants and sleep disruption.

CACNA1 encodes voltage-gated calcium channels regulating neuronal excitability and neurotransmitter release.

Variants are implicated in bipolar disorder, schizophrenia, depression, autism, and migraine — a shared genetic architecture that challenges rigid diagnostic categories.

Informs magnesium status (the natural calcium channel modulator), strategies for cortical excitability, and migraine prevention approaches.

GABRA2 codes for the alpha-2 subunit of the GABA-A receptor — the primary target of benzodiazepines and alcohol's anxiolytic effect.

Variants are associated with increased anxiety, insomnia, and greater vulnerability to alcohol dependence — particularly when alcohol is used as anxiety self-medication.

Informs non-addictive anxiety strategies: magnesium glycinate, L-theanine, glycine, sleep architecture, and nervous system regulation practices.

The D1 receptor is the most abundant dopamine receptor in the brain, driving working memory, motivation, and reward-based learning. Two SNPs are tested to capture both receptor density and promoter activity.

Variants alter receptor expression and are implicated in addiction vulnerability, ADHD, and schizophrenia risk.

Informs reward-sensitivity profile, the use of structured novelty and achievement, and protective strategies around substance reinforcement.

The D2 receptor is central to reward processing. The Taq1A A1 allele is associated with 30-40% reduced D2 receptor density, a phenotype dubbed "reward deficiency syndrome".

A1 carriers show increased risk of alcohol, nicotine, cocaine, opioid, and food addiction, compulsive gambling, and obesity — all expressions of the same neurobiology seeking stimulation the brain doesn't easily produce.

Reframes "willpower" as neurobiology. Carriers benefit from tyrosine, sunlight, structured achievement, cold exposure, exercise, and meaningful engagement — all proven D2 density enhancers.

The D3 receptor is concentrated in limbic regions governing emotional learning and reward prediction error.

The Gly9 variant is associated with altered antipsychotic response, tardive dyskinesia risk, and vulnerability to stimulant addiction.

Refines addiction risk profiling, particularly for stimulants, and informs integrative mental health strategy.

The D4 receptor is expressed in the prefrontal cortex and is associated with novelty-seeking temperament, attention, and impulsivity.

Variants are implicated in ADHD, novelty-seeking personality, and susceptibility to behavioural and substance addictions.

Informs work structure, environmental stimulation needs, and the use of adventurous-but-constructive outlets in managing addictive temperament.

CHRNA3 codes for a subunit of the nicotinic acetylcholine receptor. Variants dramatically alter nicotine response and dependence liability.

Risk alleles increase smoking intensity, dependence severity, and lung cancer risk even at the same level of exposure. This is one of the strongest genetic cancer-risk signals known.

Creates a compelling biological argument against any nicotine initiation and supports aggressive cessation strategy in current smokers or vapers.

CHRNA5 sits in the same nicotinic receptor cluster as CHRNA3 and independently influences nicotine reward and intake.

The Asn398 variant is strongly linked to heavy smoking phenotype, early-onset smoking, and significantly elevated lung cancer risk in smokers.

For families with smoking history, this is a critical signal for adolescent prevention. Informs urgency of cessation support and screening.

The mu-opioid receptor mediates the euphoric and analgesic effects of endogenous endorphins, opioid medications, and — in part — alcohol.

The Asp40 (G) variant increases the rewarding response to alcohol and opioids, increasing dependence risk but also predicting strong response to naltrexone treatment.

Extremely relevant for anyone with family alcohol history, chronic pain requiring medication, or post-surgical opioid exposure. Also informs integrative strategies for pain and pleasure regulation.

CB1 is the primary target of THC and the main cannabinoid receptor in the brain, regulating anxiety, appetite, pain perception, and memory.

Variants modify cannabis subjective response, dependence risk, and propensity for cannabis-induced anxiety or paranoia. Also relevant to endocannabinoid tone in chronic pain and anxiety disorders.

Alongside AKT1 and FAAH, provides a comprehensive cannabis risk profile particularly important given widespread cannabis legalisation.

Fatty acid amide hydrolase breaks down anandamide — the body's own "bliss molecule" and natural cannabinoid.

The A allele reduces FAAH activity, producing higher baseline anandamide levels — associated with lower anxiety, reduced pain sensitivity, and paradoxically greater risk of cannabis and other substance use disorders.

Explains individual differences in baseline anxiety, pain tolerance, and emotional resilience at the molecular level. The AA genotype is a beneficial variant — carriers naturally maintain higher anandamide ("bliss molecule") levels, experiencing lower baseline anxiety, better stress recovery, and reduced pain sensitivity. A genuinely enviable genotype.

XRCC1 is a scaffold protein essential for base excision repair (BER) — the pathway that corrects oxidative damage to individual DNA bases caused by UV radiation, pollution, and metabolic stress.

The Q399R variant reduces repair efficiency, allowing UV-induced lesions to accumulate. Each unrepaired lesion is a potential step toward skin cancer or accelerated photoageing.

Carriers benefit from aggressive photoprotection (broad-spectrum SPF 30+ daily, protective clothing), topical DNA repair enzymes (photolyase, endonuclease-containing sunscreens), and high antioxidant intake to reduce oxidative DNA assault at source.

The R280H variant affects a different functional domain of XRCC1, independently impairing BER at a second site on the protein.

Compound variants at both XRCC1 positions (Q399R + R280H) produce additive repair deficits, significantly raising skin cancer risk beyond either alone.

Reinforces the same protective strategy but with greater urgency: mineral sunscreen (zinc oxide, titanium dioxide), avoidance of peak UV hours, and consideration of oral photoprotection (Polypodium leucotomos, astaxanthin).

Human 8-oxoguanine glycosylase excises 8-oxoguanine — the most common and most mutagenic oxidative DNA lesion, generated by UV and ROS exposure. If not repaired, it causes G→T transversion mutations that initiate cancer.

The Cys326 variant reduces glycosylase activity, allowing 8-oxoG to persist in skin cell DNA. Linked to increased risk of melanoma, basal cell carcinoma, and lung cancer.

In combination with XRCC1 variants, defines the "poor DNA repair" phenotype. Supports antioxidant density (green tea EGCG, lycopene, vitamin C), sunscreen compliance, and regular dermatological surveillance.

Telomerase reverse transcriptase maintains telomere length — the protective caps on chromosome ends that shorten with each cell division. When telomeres critically shorten, cells enter senescence or die.

Variants affect telomerase activity, influencing the rate of replicative skin ageing and the skin's regenerative capacity after damage.

Wild-type carriers have a beneficial genotype with maintained telomerase activity supporting cellular regeneration. Variant carriers should prioritise telomere-protective strategies. For all genotypes, this informs the urgency of telomere-protective strategies: stress management, sleep, omega-3 DHA, vitamin D, and minimising inflammatory/oxidative burden. Also relevant to stem cell treatments and regenerative dermatology.

ASIP competes with α-MSH at the MC1R receptor, switching melanocytes from producing eumelanin (brown-black, photoprotective) to pheomelanin (red-yellow, photosensitive). Two SNPs are tested to capture both regulatory and coding variants.

Variants that increase ASIP expression shift the melanin balance toward pheomelanin, reducing natural UV protection and increasing photodamage susceptibility — even in people who tan and don't appear "fair".

Informs sun protection urgency beyond visible skin tone, freckling patterns, and melanoma risk. These variants explain why some olive-skinned individuals still burn and develop pigment irregularities.

Interferon regulatory factor 4 regulates melanogenesis and is a major determinant of freckling, sun sensitivity, hair colour, and melanoma susceptibility.

The T allele is strongly associated with sun sensitivity, freckling, lighter natural hair colour, and elevated melanoma risk independent of other pigment genes.

Alongside ASIP, MC1R, MATP, and TYR, builds a comprehensive pigmentation and melanoma risk profile. High-risk carriers benefit from annual mole mapping and dermatological surveillance.

Membrane-associated transporter protein moves tyrosine and other melanin precursors into melanosomes. Variants alter melanin production efficiency and are among the strongest determinants of skin and eye colour in European populations.

The derived allele is associated with lighter pigmentation, reduced melanin density, and higher UV sensitivity.

Part of the comprehensive pigmentation genotype that determines inherent photoprotection capacity. Informs the SPF level, reapplication frequency, and UV avoidance strategy appropriate to your biology.

Melanocortin-1 receptor determines the ratio of eumelanin to pheomelanin produced by melanocytes. It is the most studied gene in human pigmentation and skin cancer genetics.

MC1R variants (especially R/R alleles) shift melanin production toward pheomelanin, producing fair skin, red hair, and freckling — but critically, they also increase melanoma risk through UV-independent oxidative pathways. This means MC1R carriers face elevated melanoma risk even with perfect sun avoidance.

One of the most clinically significant skin genes. Wild-type CC carriers enjoy a beneficial genotype with robust eumelanin production and stronger inherent UV protection. Variant carriers benefit from aggressive photoprotection, antioxidant-dense diet and skincare, regular full-body skin checks, and awareness that melanoma risk is partly constitutive (not just behavioural).

Tyrosinase catalyses the first and rate-limiting step in melanin biosynthesis — converting tyrosine to DOPA, then DOPA to dopaquinone. Without functional tyrosinase, melanin cannot be made.

Common variants reduce TYR activity, lowering melanin production and natural UV shield. Severe mutations cause oculocutaneous albinism, but milder variants simply reduce tanning capacity and increase photodamage susceptibility.

Completes the six-gene pigmentation panel (ASIP, IRF4, MATP, MC1R, TYR, plus IL-6/inflammation overlap). Together they define your skin's inherent UV defence capacity and personalise the level of photoprotection you truly need.

CYP11A1 (cholesterol side-chain cleavage enzyme) performs the first and rate-limiting step in all steroid hormone synthesis — converting cholesterol into pregnenolone in the adrenal glands, gonads, and placenta. Every steroid hormone downstream (cortisol, DHEA, testosterone, oestrogen, progesterone) depends on this gate.

Variants alter the promoter region, affecting how much enzyme is produced and at what rate steroidogenesis can proceed. Low-activity variants may contribute to low pregnenolone, adrenal insufficiency symptoms, and poor stress hormone recovery.

This is the "headwaters" of the steroid cascade. Variants here affect everything downstream and inform decisions about DHEA, pregnenolone, and adrenal support strategies.

CYP17A1 performs two critical reactions: 17α-hydroxylation (converting pregnenolone and progesterone into their 17-OH forms) and 17,20-lyase activity (converting 17-OH pregnenolone into DHEA). It is the fork in the road that determines whether steroid flux goes toward cortisol or toward androgens/oestrogens.

The C allele increases CYP17A1 activity, driving more DHEA and androgen production. Linked to earlier menarche, higher oestradiol levels, and increased breast cancer risk. In men, linked to prostate cancer susceptibility.

Informs oestrogen management in PCOS, endometriosis, fibroids, and breast cancer risk. Also relevant to men with elevated DHT and prostate concerns. Helps interpret DHEA-S and testosterone blood work in clinical context.

Aromatase converts androgens (testosterone, androstenedione) into oestrogens (oestradiol, oestrone). It is expressed in the ovaries, testes, fat tissue, breast, bone, and brain — making it one of the most widely relevant hormone enzymes.

Variants increasing aromatase activity raise oestrogen production, particularly in men with visceral fat (oestrogen dominance, gynaecomastia) and women with oestrogen-driven conditions (endometriosis, fibroids, breast cancer). Variants decreasing activity may contribute to low oestrogen in menopause and low bone density.

Central to HRT and TRT decisions. Also informs whether aromatase inhibitors (pharmaceutical or botanical like chrysin, grape seed extract) are appropriate, and whether visceral fat loss should be aggressively prioritised for hormonal management.

3β-hydroxysteroid dehydrogenase type 1 converts DHEA to androstenedione and pregnenolone to progesterone. It sits at a major branching point governing both androgen and progesterone flux.

The gain-of-function variant accelerates conversion of adrenal androgens to potent androgens in peripheral tissues — a key driver of castration-resistant prostate cancer in men and androgen excess in PCOS.

For men: prostate cancer screening urgency and caution with DHEA supplementation. For women: PCOS androgen management and progesterone production capacity. Informs whether DHEA replacement is safe or contraindicated.

SHBG binds testosterone, DHT, and oestradiol in the bloodstream, controlling how much "free" (bioactive) hormone is available to tissues. Higher SHBG = less free hormone; lower SHBG = more free hormone activity.

Variants affecting SHBG levels dramatically change the clinical picture of "normal" total testosterone or oestradiol readings. A man with "normal" total testosterone but low SHBG may actually have high free testosterone and DHT-driven issues (hair loss, prostate). A woman with low SHBG may have hyperandrogensim despite "normal" total androgen levels.

SHBG genotype is essential for interpreting hormone blood panels correctly. It determines whether total hormone levels tell the truth — or lie. Informs the decision to test free testosterone and free oestradiol alongside totals.

Organic anion transporting polypeptide 1B1 is the liver's uptake transporter for conjugated oestrogens, bilirubin, thyroid hormones, and statins. It controls how efficiently the liver clears circulating hormones and drugs.

Variants reduce hepatic uptake, slowing oestrogen clearance (raising levels) and dramatically increasing risk of statin-induced myopathy (muscle damage). This is a pharmacogenomic crossover gene — relevant to both hormone management and cardiovascular medication.

Essential before starting statin therapy or HRT. Carriers may need lower statin doses, alternative statin choices, or modified oestrogen delivery (transdermal vs oral) to avoid hepatic first-pass accumulation.

PROGINS is a complex variant in the progesterone receptor gene (PGR) that produces a receptor with reduced sensitivity to progesterone. Two SNPs define the PROGINS haplotype, both tested on GrowBaby.

Reduced progesterone receptor function means the body needs more progesterone to achieve the same effect — critical in pregnancy where progesterone maintains the uterine lining, prevents miscarriage, and supports fetal development. Also linked to endometriosis, fibroids, and ovarian cancer.

Informs the use of progesterone support in early pregnancy, IVF protocols, and preconception planning. Also relevant to hormonal contraception choices and endometriosis management.

Factor V is a clotting factor. The Leiden mutation produces a Factor V resistant to inactivation by Protein C, meaning the clotting cascade continues longer than it should. Heterozygous carriers have 5-10x increased thrombosis risk; homozygotes have 50-80x risk.

Factor V Leiden is the most common inherited thrombophilia in European populations (~5% carrier rate). Carriers on oral contraceptives face 30-50x increased blood clot risk — making this test potentially life-saving before any OCP or oestrogen-containing HRT prescription.

Non-negotiable screening before OCP, HRT, or pregnancy (where thrombosis risk already rises physiologically). Carriers should avoid oestrogen-containing contraception and opt for progesterone-only or non-hormonal alternatives. Long-haul flight precautions, surgical DVT prophylaxis, and postpartum anticoagulation may be warranted.

The 20210 G>A variant in the prothrombin gene produces elevated prothrombin levels, amplifying the clotting cascade and raising basal thrombosis risk.

Around 2% of European populations carry this variant. Combined with Factor V Leiden, the thrombosis risk becomes multiplicative rather than additive. Also carries an independent risk of recurrent miscarriage, placental abruption, and pre-eclampsia.

Like Factor V Leiden, this is a non-negotiable test before oestrogen therapy, pregnancy planning, or surgical intervention. Carriers benefit from aspirin consideration (under medical guidance), compression strategies for long travel, and close obstetric monitoring in pregnancy.

Mitochondrial DNA is inherited exclusively from your mother — an unbroken matrilineal chain stretching back tens of thousands of years. Your mtDNA haplogroup identifies which ancient maternal lineage you descend from, where she lived, how she migrated, and what environment shaped her mitochondria. Because mitochondria generate your cellular energy, these aren't neutral historical curiosities — they're functional biological signatures of the climate, diet, altitude, and pathogen landscape your maternal ancestors adapted to.

Knowing your haplogroup lets you visualise the environment your mitochondria evolved to thrive in. A Near Eastern haplogroup like U6 (~15,000 years old) evolved amid arid, seasonal, hunter-gatherer conditions — high wild game and fish, seasonal plant foods, intense sunlight, and fasting cycles. A Northern European haplogroup adapted to cold, low light, fermented dairy, and long winters. This context informs which dietary patterns, light exposure, temperature ranges, and movement patterns your metabolism may be best calibrated for.

Your mtDNA haplogroup contextualises everything else in this library. It helps answer "what did my body evolve to eat?" and "what environment does my metabolism expect?" It also offers deeply personal insight — seeing your mother's mother's mother's migration path mapped across continents, from ancient nomadic hunter-gatherers to the world you live in today.

While mtDNA traces one maternal line, autosomal DNA analysis uses approximately 700,000 ancestry-informative SNPs compared against curated reference populations to paint the full picture of your geographic and cultural origins — covering roughly 10 generations (~200-500 years) across all ancestral lines. The methodology is highly accurate, matching your genome against verified reference datasets to reveal the specific populations, regions, and cultures your DNA comes from.

Your results might reveal a blend of South Asian, Finnish, Germanic, and British-Irish heritage — each carrying distinct metabolic signatures: hunter-gatherer influences (higher fat tolerance, cold adaptation), Neolithic farming admixtures (grain and dairy processing), or pastoralist heritage (fermented food metabolism). This isn't just trivia. It reveals the evolutionary pressures that selected your gene variants — why you carry certain FADS1, MCM6, HFE, or VDR alleles, and what dietary and environmental context they were optimised for.

Ancestry gives nutrigenomics its deepest context. When you see that your methylation variants, lipid genes, and immune genes were shaped by specific ancestral environments, your personalised protocol stops being a list of supplements and becomes a coherent story about returning your body to the conditions it was built for — adapted to your modern life.