KL is known as the Klotho gene, named for one of the Greek Fates, encodes type-I membrane protein that is related to β-glucuronidases. Mutations in this protein are associated with ageing-related decline, bone loss, and degenerative processes in chronic renal failure(CRF). The KL-VS allele has been associated with coronary artery disease susceptibility and intelligence .
Intelligence effects links to a combination of F352V and C370S http://www.cell.com/cell-reports/fulltext/S2211-1247(14)00287-3#
And this is plausible, as the HapMap frequencies are nearly identical, so either one can be considered a proxy for the other.
[PMID 22260450] Klotho gene delivery suppresses Nox2 expression and attenuates oxidative stress in rat aortic smooth muscle cells via the cAMP-PKA pathway.
[PMID 23041151] The secreted Klotho protein restores phosphate retention and suppresses accelerated aging in Klotho mutant mice.
[PMID 23093094] Acute kidney injury transcriptomics unveils a relationship between inflammation and ageing.
[PMID 23085347] Amelioration of uremic toxin indoxyl sulfate-induced endothelial cell dysfunction by Klotho protein.
[PMID 23023628] [Nutrition and Phosphorus - New progress and problem - . A potential link between phosphate and aging]