The weakness of our hypothesis is that we have no data on which polymorphisms linked to APOL1 are the best candidates for “genetic hitchhiking.” We also acknowledge that our study does not rule out all current models in which APOL1 causes FSGS in concert with a gene-environment interaction, such as a specific viral co-infection, and it is possible that this unknown virus or environmental effect is not endemic to Eastern Maharashtra, India. Here, APOL1 is linked to coinfection.