Nineteen case-control studies investigated the effect of genetic variants on the risk of hyperfiltration, decreased eGFR (defined as GFR <60 mL/min/1.73m2), chronic kidney disease (CKD) stage, kidney failure (defined as GFR <15 mL/min/1.73m2 or need for replacement therapy), or end-stage renal disease (ESRD) (if cut-off for GFR was not defined in the study): APOL1 (n = 6), MYH9 (n = 1), HMOX1 (n = 6), alpha-thalassemia (n = 6), BCL11A (n = 2), Duffy genotype (n = 3), HbS haplotypes (n = 2), and others (n = 6). The gene discussed is APOL1; the disease is alpha thalassemia spectrum.