Aortic Aneurysm, Familial Abdominal, 4
For a phenotypic description and a discussion of genetic heterogeneity of abdominal aortic aneurysm, see AAA1 (100070).
MappingBown et al. (2011) performed a genomewide association study in 1,866 patients with abdominal aortic aneurysm (AAA) and 5,435 controls, and performed replication analysis of 9 promising signals (p less than 10(-5)) in 2,871 additional AAA cases and 32,687 controls, with further follow-up in 1,491 AAA cases and 11,060 controls. The lead SNP at 1 of the 9 loci, rs1466535, located within intron 1 of the LRP1 gene (107770) on chromosome 12q13.3, demonstrated significant association in the replication sample (p = 0.0042), with confirmation in the follow-up study (p = 0.035). In a combined analysis, rs1466535 had a consistent effect size and direction in all sample sets (combined p = 4.52 x 10(-10); odds ratio, 1.15). No associations were seen for either rs1466535 or the 12q13.3 locus in independent association studies of coronary artery disease (see 607339), blood pressure (see 145500), diabetes (see 125853), or hyperlipidemia (see 144250), suggesting that this locus is specific to AAA. Gene expression studies showed a trend towards increased LRP1 expression for the CC genotype in arterial tissues, with a significant increase in LRP1 expression in CC homozygotes compared to TT homozygotes in aortic adventitia (1.19-fold; p = 0.029). Electrophoretic mobility-shift assay indicated that the rs1466535 T allele might disrupt a binding site for SREBP1 (184756).