We conclude that the fraction of homozygous mutations detected in NPHS1 and PLCE1 in patients with infantile nephrotic syndrome (27%) using the homozygosity mapping approach in outbred individuals prospectively was similar to the one reported by diagnostic sequencing (22.5% for NPHS1 and 28% for PLCE1). The gene discussed is NPHS1; the disease is nephrotic syndrome.