APOL1 and Nephropathy: The presence of variants of the APOL1 gene is possible in the homozygous (G1/G1 orG2/G2), compound heterozygote (G1/G2) or heterozygote (G1/G0 or G2/G0) forms.Patients present an increased risk of nephropathy only in homozygous and compoundheterozygote genotypes (presence of two risk alleles); therefore, these forms werecalled high risk genotype (HRG).