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).
For a few years this was the pharmacogenomic test people actually ordered: it predicted who would respond to interferon. Then the drugs changed, and a marker that once decided treatment became a historical curiosity. That is the most useful thing this page has to say.
Read more → CancerA protective allele rather than a risk one, and stronger for one subtype than for the disease as a whole. As with breast cancer, the genetics that changes decisions is BRCA — this is the other kind.
Read more → CancerThe genetics that changes what anyone does about breast cancer is BRCA1 and BRCA2 — rare, strong, and tested for properly. The variants here are the other kind: common, weak, and useful for understanding the disease rather than for deciding anything.
Read more → AutoimmuneA rare autoimmune disease that hardens skin and internal organs. Both variants here sit in the interferon and T-cell signalling machinery that also turns up in lupus and rheumatoid arthritis — the same immune wiring, a different disease.
Read more → CardiovascularThe positions here were found by asking three different questions — who develops furred arteries, who has a heart attack early, and who has a heart attack given furred arteries. The answers were not the same genes, which is the most useful thing this page has to say.
Read more → AutoimmuneAn immune reaction to gluten that damages the small intestine. Nearly everyone who has it carries particular HLA types — and so do a third of people who do not, which is exactly why the genetics rules the disease out rather than in.
Read more → AutoimmuneAn autoimmune disease that can affect almost any organ, with strong genetic involvement and dozens of known loci that together still explain a small share of it. The variant here was found in Asian populations, which is less common than it should be in this field.
Read more → CancerCommon in older men, often slow enough never to cause harm, and hard to screen well for exactly that reason. The variant here is one of the few reported to associate more strongly with the aggressive form than with the indolent one.
Read more → CancerOdds ratios of 1.06 and 1.09 — small enough that the honest use of this page is to explain what a common cancer variant is, and to point at the two things that actually work: screening on schedule, and knowing whether Lynch syndrome runs in the family.
Read more → CancerSmoking causes most lung cancer and quitting helps at any age — neither fact depends on a genotype. The interesting genetics is one locus in the nicotine receptor cluster, and an argument from 2008 about whether it acts through smoking or through the lung that has never been fully settled.
Read more → CardiovascularMore than two thousand positions have been linked to blood pressure and together they still lose to a cuff on your arm. Two of the three here came from an east Asian study — unusual on a site whose evidence is mostly European — and two of them sit in the same gene, found on different continents by groups asking different questions.
Read more → TraitWhen puberty starts is heritable, polygenic, and moved by years within a century — which tells you how much of it is not genetic. One of the variants here is the same position this site carries for obesity, and that overlap is the mechanism, not a coincidence.
Read more → TraitThe textbook polygenic trait, with the number usually left out: 12,111 positions, none of which means anything alone. It is also the clearest demonstration of why a genetic score built in one population predicts badly in another.
Read more → TraitOne position explains most of whether eyes are blue or brown — which is why the brown-dominant, blue-recessive square from school is wrong. The same genes that shade normal color cause albinism when they break outright.
Read more → AutoimmuneAn autoimmune disease that destroys the cells making insulin. It shares a word with type 2 diabetes and almost nothing else — different age, different cause, different genetics, and a much stronger inherited component.
Read more → CardiovascularCommon variants move the heart's recovery time by a millisecond or two — nothing on their own. They start to matter when a medicine pushes in the same direction, which several hundred medicines do.
Read more → BehaviouralGenetics has little to say about whether someone starts smoking and quite a lot to say about how heavily they smoke once they do — and, unusually, something practical about which quitting medicine is likely to work better.
Read more → MetabolicOne in nine adults worldwide lives with diabetes, and the great majority of it is type 2. Hundreds of variants each nudge the risk a little — and what you eat, which your genes also have a say in, does more.
Read more → SensoryThe bitter taste receptor T2R38 is not only on the tongue. It also lines the sinuses, where it detects bacterial signalling molecules and answers with nitric oxide — and the genotype that tastes nothing defends the sinuses less well.
Read more → ImmunologicA lifelong inflammatory bowel disease that can affect any part of the digestive tract. Its genetics are unusually well mapped — NOD2 was the first susceptibility gene ever found for a common complex disease, and IL23R showed a drug class where to aim.
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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.