A significant disparity in the frequency of FSGS between African Americans and people of European ancestry is well described [13]. African Americans have approximately four times the risk of FSGS compared to European Americans. Recent work [14,15] studying the genetics of this disparity by admixture analysis identified a region of chromosome 22 with excess African ancestry in the genome of African American patients. These studies have suggested that a specific haplotype near the MYH9 gene and located within this region of increased African ancestry, denoted E-1, associates with FSGS and other non-diabetic kidney diseases, including human immunodeficiency (HIV)-associated nephropathy and hypertensive renal disease, in African Americans. While the genetic penetrance and absolute risk of FSGS to an individual with the E-1 haplotype is relatively low, the population attributable risk can be considered to be high.
