Continuously updated · last reviewed Sep 5, 2026
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. 27 conditions so far, growing continuously, and free to reuse with attribution (CC BY 4.0).
3 results in Sensory
Three 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 → 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 → SensoryOdorant 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.
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