Genetic Variation Increases CKD Risk in African Americans

New research found that genetic variations in some African Americans with chronic kidney disease may lead to a more rapid decline in kidney function compared with Caucasian Americans.

The research, led by investigators from the University of Maryland School of Medicine and Johns Hopkins University, may help explain the increased risk of progressive kidney disease in African Americans, at least partly explaining a racial disparity in end-stage renal disease (ESRD), investigators reported here.

Results are published online Saturday in the New England Journal of Medicine.

Analysis of black and white patients in another trial -- half with diabetes -- showed kidney function declined almost three times as fast in blacks with the high-risk APOL1 profile as compared with whites, researchers reported at the American Society of Nephrology Kidney Week.

"What we found is pretty remarkable-that variations in a single gene account for a large part of the racial disparity in kidney disease progression and risk for end-stage kidney disease," says co-lead author and nephrologist Afshin Parsa, M.D., M.P.H., assistant professor of medicine and member of the Program in Personalized and Genomic Medicine at the University of Maryland School of Medicine.

"If it were possible to reduce the effect of this gene, there could be a very meaningful decrease in progressive kidney and end-stage kidney disease within blacks."

According to Dr. Parsa, approximately 13 percent of the African American population has two copies of the risk variants, according to the Medical Express.

The researchers analyzed the role of APOL1 gene variants in two longitudinal studies of patients with kidney disease: the Chronic Renal Insufficiency Cohort (CRIC) and the African American Study of Kidney Disease and Hypertension (AASK).

"In CRIC," says Dr. Parsa, "we found that, indeed, the gene variants account for a very significant portion of the faster progression in blacks versus whites. If a person had two copies of the APOL1 risk variant, their kidney disease worsened faster and their chance of developing end-stage kidney disease nearly doubled." The researchers also found that APOL1 variants equally affected progression rates in patients with diabetes, a finding that had not been fully realized in previous studies. "These results suggest that APOL1 gene variants affect the progression of established renal disease, regardless of the primary cause," adds Dr. Parsa.