rs4340 is one of four SNPs representing perhaps the best studied ACE SNP. It is actually not a single nucleotide polymorphism at all; instead, it is an insertion/deletion of an Alu repetitive element in an intron of the ACE gene. Alleles containing the insertion are called "I" alleles, and "D" alleles lack the repetitive element. The other dbSNP entries all tagging this same single insertion/deletion SNP are:
There are numerous association studies reported for these SNPs. Examples:
- (I;I) homozygotes respond better to Viagra than (D;I) or (D;D) individuals, in a study of 100+ Caucasian men with erectile dysfunction. (OR 3.07, CI: 1.03 - 9.13, p=0.04). [PMID 12837457]
- (I;I) homozygotes are are higher risk for early-onset psoriasis, with an odds ratio of 1.88 (CI: 1.12-3.15, p=0.016).[PMID 18031458]
[PMID 18333655] (I) is found more commonly in sherpas
[PMID 20570668] Genetic associations with mountain sickness in Han and Tibetan residents at the Qinghai-Tibetan Plateau
[PMID 21722816] Contribution of Deletion in Angiotensin-converting Enzyme But Not A1166C Angiotensin II Type-1 Receptor Gene Polymorphisms to Clinical Outcomes in Atherothrombotic Disease [PMID 17092869] Haplotype structure of five SNPs within the ACE gene in the Tunisian population.
[PMID 18637188] RAS gene polymorphisms, classical risk factors and the advent of coronary artery disease in the Portuguese population.
[PMID 18805939] Functional genetic polymorphisms and female reproductive disorders: part II--endometriosis.
[PMID 18974842] Gender differences in genetic risk profiles for cardiovascular disease.
[PMID 22908855] The linkage disequilibrium pattern of the angiotensin converting enzyme gene in Arabic and Asian population groups [PMID 23107763] Host genetic risk factors for community-acquired pneumonia.