In children, mutations in genes such as NPHS1 and NPHS2, which encode for structural proteins nephrin and podocin respectively, as well as the WT1 gene, which is involved in podocyte development, have been identified as the major genetic causes of FSGS, as detection rates of up to 24% have been reported (1, 9, 91). Here, WT1 is linked to focal segmental glomerulosclerosis.