The overall mutation detection rate was high at 57% (97% in CNS and 41% in SRNS); 85% of all mutations were identified by the analysis of three single genes only (NPHS1, NPHS2, and WT1), accounting for 92% of all mutations in patients with CNS and 79% of all mutations in patients with SRNS.
The human ortholog encodes a transmembrane protein containing five extracellular immunoglobulin-like domains that is structurally related to human NEPHRIN, a protein associated with congenital nephrotic syndrome.
The aim of this study was to confirm that the NPHS1 gene is responsible for congenital nephrotic syndrome in our population, applying homozygosity mapping.
Mutations in NPHS1, which encodes nephrin, are the main causes of congenital nephrotic syndrome (CNS) in Finnish patients, whereas mutations in NPHS2, which encodes podocin, are typically responsible for childhood-onset steroid-resistant nephrotic syndrome in European populations.
This study demonstrates that the urinary proteome of pediatric RCAD patients differs from autosomal dominant polycystic kidney disease (PKD1, PKD2), congenital nephrotic syndrome (NPHS1, NPHS2, NPHS4, NPHS9) as well as from chronic kidney disease conditions, suggesting differences between the pathophysiology behind these disorders.
Congenital nephrotic syndrome (CNS) is primarily a monogenetic disease, with the majority of cases due to changes in five different genes: the nephrin (NPHS1), podocin (NPHS2), Wilms tumor 1 (WT1), laminin ß2 (LAMB2), and phospholipase C epsilon 1 (PLCE1, NPHS3) gene.
Recent studies have shown that congenital nephrotic syndrome may be secondary to mutations of one of these three genes and that some patients have a digenic inheritance of NPHS1 and NPHS2 mutations.
The phenotypic variance of patients with congenital nephrotic syndrome with nephrin and podocin mutations resulting from triallelic mutations represents an important advance in our understanding of the effect of multiple genetic mutations on clinical disease expression.
Pierson syndrome is caused by mutations in the LAMB2 gene, which encodes the laminin beta2 chain, and is clinically characterized by congenital nephrotic syndrome (CNS) and bilateral microcoria.
Mutation of the LAMB2 gene is associated with Pierson syndrome, which is an autosomal recessive disorder characterized by congenital nephrotic syndrome and ocular abnormalities.
What is known • LAMB2 mutations are associated with Pierson syndrome • Pierson syndrome is associated with congenital nephrotic syndrome, microcoria and neurological deficits What is new • A novel mutation in the LAMB2 gene in two female siblings • Genotype and clinical phenotype description of a novel LAMB2 mutation.
The overall mutation detection rate was high at 57% (97% in CNS and 41% in SRNS); 85% of all mutations were identified by the analysis of three single genes only (NPHS1, NPHS2, and WT1), accounting for 92% of all mutations in patients with CNS and 79% of all mutations in patients with SRNS.
In contrast, patients with LAMB2 missense mutations, such as R246Q, can have less severe extrarenal defects but still exhibit congenital nephrotic syndrome.