Each page covers one condition properly: what it actually is and what it feels like, what causes it, how common it really is and in whom, and how it's diagnosed — followed by the specific variants with a replicated link to it, and, where the research supports it, how genetics can change the way a medicine behaves.
Written in two registers so one page serves both readers: plain language first, then a clinical detail section with the precise terminology, effect sizes and diagnostic thresholds. Every claim is sourced from freely-available published research and cited on the page, so you can check us — or hand the page to your doctor. 385 conditions so far, growing continuously, and free to reuse with attribution (CC BY 4.0).
Odorant receptors are the largest gene family in the human genome, and they differ enormously between people. The result is that two people can meet the same molecule and only one of them smells anything at all.
Read more → SensoryThree coding changes in one bitter receptor gene decide whether compounds like PTC and PROP taste intensely bitter or of almost nothing. It is the strongest genetic association on this site, and one of the oldest known human polymorphisms.
Read more → DermatologicHow two pigmentation variants (IRF4 rs12203592 and SLC45A2 rs16891982) relate to freckling and sun sensitivity, what they do and do not say about melanoma and skin cancer risk, and why early detection matters most.
Read more → CardiovascularCommon variants near the APOA5 gene are associated with modestly higher average triglyceride levels. They contribute a small shift, not a diagnosis, and very high triglycerides mainly matter because of pancreatitis risk.
Read more → PharmacogenomicsA common OPRM1 variant alters the mu-opioid receptor and has been studied in relation to opioid dose requirements and naltrexone response, but CPIC found the evidence too weak and inconsistent to support any clinical dosing recommendation.
Read more → PharmacogenomicsA common CYP1A2 variant affects how quickly the body clears caffeine. A widely repeated claim that 'slow' metabolizers face higher heart-attack risk from coffee rests on limited evidence that has not held up well in larger studies.
Read more → NutritionalWhat vitamin D does, why medical bodies disagree on where "deficiency" begins, who is actually at risk, and why a common GC gene variant nudges measured vitamin D levels modestly without diagnosing deficiency on its own.
Read more → TraitThe ABO gene variant that creates blood type O by disabling its enzyme, why blood type matters for transfusion, and which disease links (clotting risk, malaria, cholera) are strong versus which (COVID-19, cancer risk) remain modest or contested.
Read more → HematologicA promoter variant that silences the Duffy antigen on red cells, protecting against Plasmodium vivax malaria and causing a normal, lower neutrophil count that is routinely and wrongly treated as disease in people of African ancestry.
Read more → ImmunologicA common FUT2 variant determines whether ABO blood-group antigens appear in saliva, gut mucus and other secretions; the roughly one in five people who are "non-secretors" are strongly resistant to the dominant norovirus strains.
Read more → ImmunologicA 32-base-pair deletion in the CCR5 gene that removes a key HIV-1 entry receptor from immune cells; two copies confer strong resistance to CCR5-tropic HIV-1, while one copy slows disease progression without preventing infection.
Read more → OphthalmicGlaucoma is a group of eye diseases that silently damage the optic nerve. A variant near SRBD1 has been linked to normal-tension glaucoma in Japanese cohorts, but evidence outside that population is thin.
Read more → DermatologicMale pattern baldness is strongly heritable and linked to a variant in the androgen receptor gene on the X chromosome. That partly explains the 'blame your mother's father' folklore, but dozens of other genes also matter.
Read more → MetabolicA common variant near the FTO gene is linked to a small average increase in body weight and BMI by nudging appetite regulation. Most carriers never become obese — environment and behavior still matter most.
Read more → CardiovascularA common DNA variant near the PITX2 gene is the strongest and most consistently replicated genetic risk factor for atrial fibrillation, the most common irregular heart rhythm and a major cause of stroke.
Read more → MetabolicA common East Asian genetic variant that leaves the body unable to fully break down a toxic alcohol byproduct, causing facial flushing and, with regular drinking, a substantially elevated risk of esophageal cancer.
Read more → MetabolicWhether you can comfortably drink milk as an adult comes down largely to a single DNA switch near the LCT gene. Persistent lactase activity is the evolutionary exception in humans, not the default.
Read more → NeurologicalA common neurological sleep-related movement disorder causing an overwhelming urge to move the legs, worse at rest and in the evening and relieved by movement, which fragments sleep and often runs in families.
Read more → AutoimmuneA long-term inflammatory bowel disease in which the lining of the colon and rectum becomes inflamed and ulcerated, causing bloody diarrhoea, urgency and abdominal cramping that flare and remit over years.
Read more → PharmacogenomicsMuscle aches are the most common reason people stop taking statins. A common variant in SLCO1B1, the liver transporter that pulls statins out of the bloodstream, is linked to higher statin levels and higher myopathy risk.
Read more →Showing 20 of 385 · page 19 of 20
One diagnosed condition or measurable trait covered properly: what it actually is, what causes it, how common it is, how it is diagnosed, and the specific variants with a replicated link to it — every claim sourced from published research.
No. Every page here is informational, not a diagnosis. A result should be discussed with a doctor or a licensed genetic counselor, never acted on alone.
Because they are not disorders. Height, ABO blood group and a handful of others describe a measurable characteristic with nothing to diagnose — "Trait" says so plainly instead of implying a disease that is not one.
Only after a replicated association in published research, verified against the primary study rather than a gene name or a marketing claim — the same discipline the variant pages themselves follow.