A novel mutation of congenital nephrotic syndrome in a Slovenian child eventually receiving a renal transplant

Congenital nephrotic syndrome (CNS) is a rare disease defined as heavy proteinuria, hypoalbuminemia, hyperlipidemia, and edema presenting in the first three months of life. It is most commonly caused by mutations in the NPHS1 gene associated with nephrotic syndrome type 1, also known as Finnish-type CNS, which is inherited in an autosomal recessive manner. Symptomatic treatment with intravenous albumins, vitamins, minerals, nutritional, and hormonal supplementation and treatment of complications are mandatory. Children refractory to the symptomatic treatment are recommended to undergo nephrectomy and renal replacement therapy, preferably renal transplantation. We report on a child with Finnish type CNS with a NPHS1 mutation, which is the first case confirmed by genetic study in Slovenia. We showed for the first time that homozygous mutation c.2928-3del in the NPHS1 gene caused exon 22 skipping, leading to a truncated protein and Fin-minor phenotype.

Congenital nephrotic syndrome (CNS) is a rare form of nephrotic syndrome, presenting in the first three months of life. In most cases, it is caused by monogenic mutations of structural proteins that form the glomerular filtration barrier in the kidneys, such as gene NPHS1 (1).Pathogenic variants in the NPHS1 gene are associated with nephrotic syndrome type 1, also known as Finnish-type CNS, which is inherited in an autosomal recessive manner, with the mutations being homozygous or compound heterozygous. The syndrome is characterized by a severe steroid-resistant nephrotic syndrome apparent at birth, with rapid progression to end-stage renal failure (1,2).We report on a child with Finnish-type CNS with a NPHS1 mutation, which is the first case confirmed by a genetic study in Slovenia. The reported mutation was confirmed for the first time to be pathogenic.