Intronic NADSYN1 variant in the DHCR7/NADSYN1 vitamin D locus; T allele tags the lower-vitamin-D haplotype, reducing 7-dehydrocholesterol availability for skin vitamin D3 synthesis

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

SNCA 3′-region variant consistently associated with Parkinson's disease risk across Asian and European populations

NAT2 acetylation speed tag SNP - marks rapid vs slow acetylator haplotypes

Second TCF7L2 diabetes variant - compounds risk with rs7903146

Intronic IL33 variant where A-allele carriers showed a protective trend against childhood asthma in a Finnish birth cohort

Intronic CYP2C8 variant tagging a haplotype associated with altered taxane drug clearance and survival outcomes in chemotherapy-treated patients

Intronic variant in the FADS1 gene cluster that tags a haplotype block controlling delta-5 desaturase activity; the C allele reduces conversion of omega-6 and omega-3 precursors to long-chain PUFAs (AA, EPA) and also increases miR-1908-5p expression, independently lowering LDL cholesterol

Determines presence of alpha-actinin-3 protein in fast-twitch muscle fibers, influencing sprint/power vs endurance capacity

Splice-site variant in the circadian clock gene CRY1 that causes exon 11 skipping, producing a gain-of-function protein that lengthens circadian period by ~30 minutes and drives Delayed Sleep Phase Disorder