A genetic variant on chromosome 2 is strongly linked with kidney failure in diabetic women but not in men, according to a study appearing in an upcoming issue of the Journal of the American Society of Nephrology. The findings may help explain gender-specific differences in kidney failure, as well as why some diabetic women are prone to develop kidney failure, the study authors said.

Niina Sandholm, MSc, and Per-Henrik Groop, MD, DMSc from Helsinki University Central Hospital and Folkhälsan Research Center in Finland and their colleagues designed a study to detect genetic variants that might predispose diabetic women to kidney failure. Their initial study included 3652 Finnish patients with type 1 diabetes.

The researchers identified a genetic variant on chromosome 2 that was linked with kidney failure in women with type 1 diabetes but not in men. Additional analyses revealed that it was also linked with kidney failure in diabetic women in the United Kingdom, the United States, and Italy. Diabetic women with the risk variant had a nearly two-fold increased risk of developing kidney failure compared with diabetic women who did not have the risk variant.

"This study reports the first genetic variant robustly associated with end stage renal disease in diabetic women but not in men. This finding may give valuable information on how some diabetic women lose their protection against end stage renal disease," said Sandholm. The genetic variant is located close to a gene for a factor that interacts with the estrogen receptor and also helps regulate kidney function. It will be interesting to see if this factor plays a role in the gender-specific protection against kidney failure seen in this study.

"In identifying evidence of an association with end stage renal disease exclusively in women, this study offers the strongest evidence to date of a sex-specific genetic factor for diabetic nephropathy," Marcus Pezzolesi, PhD, and Andrzej Krolewski, MD, PhD, from the Joslin Diabetes Center, wrote in an accompanying editorial. They added, however, that the findings need to be verified by additional studies.