Cation Chloride Cotransporter 9 (CCC9)

SLC12A8 is thought to be a candidate for psoriasis susceptibility. Several alternatively spliced transcript variants of this gene have been described, but the full-length nature of some of these variants has not been determined.

By linkage disequilibrium to identify SNPs in a region of chromosome 3 associated with psoriasis, followed by database analysis, PCR amplification, and 5-prime RACE, Hewett et al. (2002) identified several SLC12A8 splice variants. The most common variant encodes a deduced 731-amino acid protein with 2 regions of homology to Na-K-Cl cotransporters, a family of membrane proteins responsible for electroneutral ion transport. PCR analysis revealed almost ubiquitous expression, with highest levels in small intestine, stomach, testis, thyroid, and colon.