APOL1 and Hypoalbuminemia: Furthermore, the twins exhibited clinical features highly characteristic of APOL1-associated nephropathy, including nephrotic-range proteinuria (7.02 g/24 h), hypoalbuminemia, hypercholesterolemia, biopsy-confirmed FSGS, and progression to dialysis, providing strong phenotypic support for its pathogenicity (PP1/PM1).