rs12696304

rs12696304 is a SNP near the TERC gene, which encodes the telomerase RNA component. A genome-wide association study of mean leukocyte telomere length in 2,917 individuals, with follow-up replication in 9,492 individuals, found that each rs12696304(G) allele was significantly (p = 3.72 × 10?14) associated with a ~75-base-pair reduction in mean telomere length, equivalent to ~3.6 years of age-related telomere-length attrition. In other words, in terms of biological aging, this report implies that individuals carrying one rs12696304(G) allele will appear 3.6 years "older", and those with two such alleles 7.2 years "older", than rs12696304(C;C) individuals, at least in terms of telomere length. Telomere shortening can lead to premature aging, in terms of increased risk for age-associated diseases such as heart disease, and at least some forms of cancer, and therefore also reduced longevity. Note that all individuals in this study were of European descent, so it is unknown if this finding will hold across different ethnicities. Furthermore, the authors estimate that their finding leaves 99% of the variation in aging to be explained by other factors. see also: NHS News Bulletin