African Americans who have chronic kidney disease (CKD) and two copies of common variants in the APOL1 gene are twice as likely to progress to kidney failure as those without these high-risk variants. Moreover, African Americans with the high-risk variants also tend to lose kidney function at twice the rate of those without the variant.
Previous studies have shown that African Americans with two copies of certain variants of the APOL1 gene are at increased risk of developing kidney disease. Researchers attempted to further characterize the nature of this increased risk by analyzing data from people enrolled in two large studies of CKD: the Chronic Renal Insufficiency Cohort (CRIC) Study and the African American Study of Kidney Disease and Hypertension (AASK). The CRIC study is one of the largest and longest ongoing studies of CKD epidemiology in the U.S.; it is following both white and African American people with CKD, about half of whom also have diabetes. AASK was the largest and longest study of CKD in African-Americans without diabetes whose CKD was attributed to high blood pressure. In the new analysis, the researchers found a correlation between the presence of high-risk variants of the APOL1 gene and an increased risk of CKD progression among African Americans. This effect was seen regardless of whether patients maintained good blood pressure control or had diabetes.
This study builds on information learned over the past few years about how genetic factors can contribute to the increased risk of kidney disease in African Americans. These results have important implications for understanding the differences in kidney disease risk across populations. Moving forward, physicians may be able to make better choices about when to start screening for kidney disease and how to choose an appropriate therapy by identifying which patients have these gene variants and are therefore at increased risk of developing kidney disease and progressing to kidney failure.
Parsa A, Kao WHL, Xie D, Astor BC, Li M, Hsu CY, Feldman HI, Parekh RS, Kusek JW, Greene TH, Fink JC, Anderson AH, Choi MJ, Wright JT Jr, Lash JP, Freedman BI, Ojo A, Winkler CA, Raj DS, Kopp JB, He J, Jensvold NG, Tao K, Lipkowitz MS, Appel LJ; AASK Study Investigators; CRIC Study Investigators. APOL1 risk variants, race, and progression of chronic kidney disease. N Engl J Med. 369: 2183-2189, 2013.