June 29 (HealthDay News) -- A gene variant that contributes to both kidney stones and osteoporosis has been identified by scientists who said the variant offers a promising target for new drugs to better regulate calcium metabolism.

The single-letter variation (SNP) occurs in the gene encoding claudin 14 (CLDN14), a protein expressed in the kidney, according to a news release.

The 60 percent of humans who carry two copies of this SNP on chromosome 21 have a 65 percent greater risk of developing kidney stones than those with no copies of the SNP. It's believed the SNP may account for more than a quarter of kidney stone cases. In women, it is associated with decreased bone mineral density in the hip and spine.

The researchers examined the genomes of about 50,000 people to learn more about the association between CLDN14 and the metabolism of calcium, a key component of bone and of most kidney stones. They concluded that the SNP may contribute to increased calcium excretion in urine, a major risk factor for kidney stones and also a sign of bone loss.

The study appears online June 28 and in an upcoming print edition of the journal Nature Genetics.

This research identified "a highly plausible common biological mechanism leading to two diseases. This offers a potentially attractive new pathway for drug discovery, and the next task is to build on our understanding of how this SNP increases the risk of these diseases and how this pathway could be targeted therapeutically to address this risk," Kari Stefansson, CEO of the bio-pharmaceutical company deCODE, said in a company news release.

SOURCE: deCODE, news release, June 28, 2009