Two Mean Kidney Genes

Kidney disease risk in African Americans increased by two genetic variants

(RxWiki News) Why are African Americans more likely than whites to develop kidney disease? Well, it may have to do with a change to a certain gene.

African Americans with two copies of a certain genetic change have a four percent risk of developing a type of kidney disease during their lifetime.

"Get screened for kidney disease."

Jeffrey Kopp, M.D., of the National Institute of Diabetes and Digestive and Kidney Diseases, Cheryl Winkler, Ph.D., of the National Cancer Institute, and colleagues studied a form of kidney disease called focal segmental glomerulosclerosis (FSGS). Patients with FSGS often develop end-stage kidney disease, which then calls for dialysis or a kidney transplant.

About 12 percent of African Americans have two variants of the APOL1 gene. The researchers found that these people have a four percent risk of developing FSGS in their lifetime.

African Americans who have no variant in the APOL1 gene, or just one variant, have about the same risk of end-stage kidney disease as white Americans, says Dr. Winkler. However, those with two copies are 17 to 30 times more likely to get certain kidney diseases.

According to Dr. Winkler, these findings almost fully explain why non-diabetic African Americans have so much more risk of kidney failure.

If African Americans with the gene variant go on to develop kidney disease, they are often diagnosed at a younger age than other patients with FSGS.

African Americans with the two APOL1 variants and HIV have a higher risk of developing a form of kidney disease called HIV-associated nephropathy (HIVAN).

The researchers also found that steroids are a feasible treatment option for FSGS patients with two APOL1 variants. These patients respond just as well to steroid treatment as those who do not have the variants.

Kidney disease progresses more quickly in patients with the two variants, which makes the researchers think that aggressive treatment may be called for.

"In the future, knowing that you have these gene variants and are at increased risk of developing kidney disease may tell you when to start screening for the disease and how to choose therapy," says Dr. Kopp. However, he continues, more studies are needed to see if early genetic testing of African Americans actually helps, and if early treatment has an effect on long-term outcomes.

The study is published in the Journal of the American Society of Nephrology

Review Date: 
October 24, 2011