rs405509

This study examined 4960 SNP triples from five genes in the APOE region (BCAM, NECTIN2, TOMM40, APOE, APOC1) in 2789 Alzheimer's disease cases and 16,334 controls using a novel co-skewness metric to identify complex haplotypes associated with AD. The authors identified 1127 significant AD-associated SNP triples, demonstrating that complex multi-SNP haplotypes—which may not include the canonical APOE ε4 or ε2 alleles—play definitive roles in AD predisposition, with the ε4 allele showing strengthened connections to other region alleles and ε2 showing weakened connections in affected subjects.

A candidate gene association study of dementia risk in 2,857 older postmenopausal women from the Women's Health Initiative Memory Study examining 96 SNPs across five genes (APOE/TOMM40, BDNF, COMT, SORL1, KIBRA). The APOE/TOMM40 locus showed the strongest association (rs157582: OR=1.64, p=2.4×10⁻⁸ for probable dementia), with additional significant associations in COMT (rs737865), BDNF (rs1491850), and KIBRA (rs4320284, rs2241368, rs244904). Results support APOE/TOMM40 as a dementia risk locus and extend associations to COMT, BDNF, and KIBRA genes.

A literature review of 70 studies examining single nucleotide polymorphisms (SNPs) associated with obesity in Mexican populations published 2011-2021. The authors identified SNPs with differential behavior in Mexican compared to Caucasian populations, including rs17782313 (MC4R), rs6548238 (TMEM18), rs6265 (BDNF), rs7498665 (SH2B1), and notably rs6232 (PCSK1) associated with early-onset obesity in Mexican youth. The review emphasizes ethnicity-dependent genetic effects on BMI heritability (40-70%) and highlights genes involved in cholesterol metabolism and adipokine signaling pathways.

A hospital-based case-control study in rural and urban India (1,204 cases; 1,212 controls) examined genetic and lifestyle risk factors for breast cancer. Four SNPs in FGFR2 (rs1219648, rs2420946, rs2981575, rs2981582) showed positive associations with breast cancer (ORs 1.32-1.47). Additional SNPs in obesity and metabolic genes (rs374748 in FBN2, rs2922763 in HNF4G, rs2116830 in KCNMA1, rs11121832 in MTHFR, rs16886165 in MAP3K1, rs11594610 in TCF7L2, rs2274459 in MLN) were associated with increased breast cancer risk. Waist-to-hip ratio ≥0.95 showed strong association (OR 3.78; 95% CI 2.92-4.89), and women living first 20 years in rural areas showed protective effect (OR 0.77).

Pooled analysis of 15 studies (n=21,160) demonstrating that the APOE ε4 haplotype is protective against late age-related macular degeneration (AMD) (OR=0.72 per haplotype, p=4.41×10^-11), while the ε2 homozygote shows increased risk (OR=1.83, p=0.04). Extended haplotype analysis incorporating rs405509 did not identify additional risks beyond ε2 and ε4 haplotypes. Smoking was a major risk factor for progression to late AMD forms.

This methodological study develops ProxyGeneLD software for converting genome-wide SNP association data to pathway-enriched gene sets and validates it on multiple large GWAS datasets. The authors demonstrate successful replication of pathway enrichment for plasma HDL levels (with CETP and ABCA1 in lipid metabolism pathways) across independent samples and identify positional gene clustering as a major source of spurious enrichment in pathway analyses of GWAS data.

This cumulative PhD dissertation investigates genetic susceptibility factors for age-related macular degeneration (AMD). The study confirms weak associations of APOE coding variants with AMD risk (P < 0.05) but finds no association with HMCN1 variants. Large replication studies of candidate genes TLR3 and SERPING1 (1,080-4,881 cases and 2,669-2,842 controls) show no association. The authors identified 15 high-risk variants in ARMS2/HTRA1 region on chromosome 10q23.33-10qter, with the ARMS2 A69S variant showing 2.7-fold increased risk heterozygously and 8.2-fold increased risk homozygously, comparable in strength to CFH Y402H. An indel variant (c.*372_815del443ins54) in ARMS2 3' UTR causes mRNA destabilization.

This linkage study of 417 affected sibling pairs with Alzheimer's disease from Sweden/Norway, UK, and USA examined chromosome 19q13. The strongest linkage peak (Zlr=3.28, P=0.036) was located 1 Mb from APOE. APOE ε4 alleles explained the linkage in the whole sample and UK/USA subsamples, though the Swedish sample showed marginal evidence of additional linkage. Age at onset had a significant effect on the linkage peak (lod increase=3.31, P=0.002), partially explained by APOE genotypes.