Regulatory 5'UTR variant in the dopamine D1 receptor gene influencing receptor density and cognitive efficiency under high cognitive load

3' untranslated region variant in IFNL3 (IL28B) that controls mRNA stability via AU-rich elements and miRNA binding — independently predicts hepatitis C spontaneous clearance and treatment response

Intronic variant in betaine-homocysteine methyltransferase gene associated with selenium levels but no known disease risk

Intronic variant tagging the HNF4A P2 promoter haplotype; carriers have modestly elevated risk for impaired insulin secretion and type 2 diabetes

Low-frequency intronic variant in FLT3 that creates a cryptic splice site, truncating the receptor in 30% of transcripts and doubling plasma FLT3 ligand per allele, substantially increasing risk of autoimmune thyroid disease (Hashimoto's) and other autoimmune conditions

Intronic variant in STAT6 (intron 2) that creates an NF-κB binding site, increasing STAT6 promoter activity; the T allele is associated with elevated total serum IgE and increased risk for atopic dermatitis, asthma, and allergic rhinitis through enhanced Th2 signaling

Near-gene variant tagging the TMPRSS3 hearing loss locus on chromosome 21, associated with susceptibility to sensorineural hearing loss and carrier status for DFNB8/10 deafness

No-function CYP2C19 stop-gain variant — second most common loss-of-function allele, highest in East Asian ancestry

Pathogenic missense variant in the cobalamin-processing enzyme; homozygosity causes cobalamin C (cblC) disease with severe methylation and detoxification failure

Intronic PTPN1 tag SNP within the 100-kb T2D-risk haplotype block — carriers of the G allele have modestly higher PTP1B activity, reducing insulin and leptin signal duration and raising LDL cholesterol risk in lean individuals