Whole exome sequencing identification of a novel insertion mutation in the phospholipase C ε­1 gene in a family with steroid resistant inherited nephrotic syndrome.

Nephrotic syndrome (NS) represents a heterogeneous group of kidney disorders characterized by excessive proteinuria, hypoalbuminemia and edema. Defects in the filtration barrier of the glomeruli results in the development of NS. The genetic cause of NS remains to be fully elucidated. However, previous studies based on positional cloning of genes mutated in NS have provided limited insight into the pathogenesis of this disease. Mutations in phospholipase C ε­1 (PLCE1) have been reported as a cause of early onset NS characterized by histology of diffuse mesangial sclerosis. In the present study, the underlying cause of NS in a consanguineous family was identified. Clinical and molecular aspects of a consanguineous Saudi family comprised of five individuals with steroid resistant NS were examined. Seven healthy individuals from the same family were also studied. Whole exome sequencing (WES) was performed to detect the genetic defect underlying NS. WES identified a homozygous novel insertion mutation (c.6272_6273insT) in the PLCE1 gene. Pedigree and segregation analysis confirmed an autosomal recessive inheritance pattern. This mutation may result in a bi­allelic loss of the C­terminal Ras­associating domain in PLCE1 that results in NS. The present study expanded the mutational spectrum of PLCE1 in NS. In addition, the present study provided further evidence that supports the important involvement of PLCE1 in the physiological function of the glomerular filtration barrier.