Worldwide Frequencies of APOL1 Renal Risk Variants

To the Editor: Risk variants in the APOL1 gene on chromosome 22, which were first discovered in African Americans, confer a substantially increased risk of kidney disease, early-onset hypertension, and cardiovascular disease, although disease risk is modified by other genetic factors and by environmental factors. 1 This is an important discovery for genomic medicine and has improved our understanding of disparities among ethnic groups. 2 Efforts are under way to incorporate APOL1 testing in routine clinical settings, and APOL1 is under consideration as a therapeutic target for kidney disease. he APOL1 risk variants rose to high frequency in Western Africa in response to trypanosomal infection, 4 and most studies of APOL1 have involved populations of persons who self-report as African or African American. However, other populations who also share recent ancestry from Africa, such as Hispanic populations, may be at greater risk than expected for APOL1-driven disease. These persons may not undergo testing; however, they may still be at high risk because of the presence of APOL1 risk variants. 5 Thus, it is important to understand more fully the global distribution of these variants on the basis of country of origin and genetic ancestry rather than self-reported race or ethnic group.