Intronic tag SNP in HLA-DQA1 in strong LD with HLA-DQA1*01:02; the G allele increases peanut allergy susceptibility by tagging the DQA1*01:02 haplotype, raises HLA-DQB1 expression in CD4+ T cells, and drives protective peanut-specific IgG4 responses when peanut is consumed early in life

Intronic MAPT variant that regulates tau exon 3 splicing via hnRNP F/Q binding, distinguishing H1 (risk) from H2 (protective) haplotypes for Parkinson's disease, PSP, corticobasal degeneration, and Alzheimer's disease

Key enzyme for converting folate to its active methylfolate form

Intronic variant tagging the HNF4A P2 promoter risk haplotype; the G allele strongly elevates type 2 diabetes risk in Ashkenazi Jewish populations (OR ~1.70) and modestly in Scandinavians (OR ~1.14) by reducing beta-cell-specific HNF4A isoform expression

Reduces vitamin K metabolism, requiring higher warfarin doses to achieve anticoagulation

Core clock gene variant that shifts circadian period length and influences morning vs evening chronotype

Intronic variant in the LYPLAL1 locus associated with waist-hip ratio and fat distribution, with sex-dimorphic effects strongest in women

Intronic variant in FADS2 (delta-6 desaturase) associated with reduced enzyme activity and impaired conversion of plant-based omega-3 (ALA) and omega-6 (LA) precursors into long-chain PUFAs, with the T allele linked to lower circulating EPA and arachidonic acid

Regulatory variant in the ANRIL long non-coding RNA at the 9p21.3 locus that influences CDKN2B expression and functional aging; the G allele is protective against physical impairment with age

Promoter variant affecting circulating IGF-1 levels and athletic performance potential