Master regulator of iron absorption via hepcidin control — the strongest common genetic determinant of iron status

3'-UTR regulatory variant in IL13 that influences IL-13 mRNA stability and expression level; the minor A allele co-segregates with the rs20541 Q130 risk haplotype and is associated with elevated serum IgE and increased susceptibility to atopic dermatitis and allergic rhinitis through amplified IL-13 Th2 signaling

Pathogenic missense variant at the TMPRSS3 autocatalytic cleavage site causing serine protease domain dysfunction and autosomal recessive sensorineural hearing loss (DFNB8/DFNB10); originally identified in consanguineous Turkish families

Pathogenic nonsense variant in HNF4A causing MODY1 — a progressive, autosomal dominant monogenic diabetes with neonatal hypoglycemia and sulfonylurea sensitivity

Missense variant in methionine synthase reductase that raises homocysteine when vitamin B12 is low, affecting B12-dependent methylation efficiency

Intronic PPARG variant — carriers of the C allele have elevated fasting glucose and higher risk of converting from impaired glucose tolerance to type 2 diabetes; the effect is substantially reduced by increased aerobic physical activity

3'-UTR variant in ELOVL2 associated with altered EPA-to-DHA conversion; A allele carriers tend to have lower baseline DHA and greater DHA response to marine omega-3 supplementation

Decreased-function variant causing reduced thiopurine methylation; pairs with TPMT*3C on the same chromosome to form the TPMT*3A haplotype, the most common cause of TPMT deficiency in Europeans

Beta-1 adrenergic receptor variant where Arg389 produces higher basal activity and stronger catecholamine response, affecting exercise heart rate, beta-blocker pharmacogenomics, and cardiovascular risk

Core circadian clock transcription factor variant affecting mRNA stability, associated with evening preference, delayed sleep onset, and shorter sleep duration