The NPHS2 gene, encoding the slit diaphragm protein podocin, accounts for 43% of familial and 10% of sporadic forms of nephrotic syndrome (NS).1, 2 Conditional inactivation of podocin in adult mice is a novel model system for NS resulting from focal segmental glomerulosclerosis (FSGS),3 which recapitulates human disease formation. This evidence concerns the gene NPHS2 and focal segmental glomerulosclerosis.