We report a consanguineous family from Saudi Arabia with three affected children presenting with infantile nephrotic syndrome. In order to provide a molecular diagnosis, a genome-wide SNP analysis of the affected patients was performed. We identified a region of homozygosity on chromosome 1, containing the NPHS2 gene. Direct sequencing, by exon PCR, of NPHS2 identified a homozygous nucleotide change 385C > T within exon 3 in the three affected children, leading to a premature stop codon (Q129X). This homozygous truncating mutation in NPHS2 is novel and was associated with a severe clinical phenotype. Additional mutations in related genes NPHS1, PLCE1 and NEPH1 were not identified, excluding tri-allelism within these genes in this family.
Keywords: NPHS2; homozygosity; nephrotic syndrome; podocin.