The differences between G1 and G2 within separate cohorts of patients and with distinct methods of phenotyping (incidence of glomerulosclerosis versus age of dialysis initiation) speaks to the genetic complexity at this locus, and if the dominance of G1 and G2 is subtle but real, then our finding of a lack of association between APOL1 null alleles and glomerulosclerosis would be less surprising. Here, APOL1 is linked to glomerulosclerosis.