Instituto Valenciano de Microbiología

Masía El Romeral
Ctra. de Bétera a San Antonio Km. 0.3
46117 Bétera (Valencia)
Phone. 96 169 17 02
Fax 96 169 16 37
CIF B-96337217


Nephrotic type 1 syndrome, congenital nephrosis Finnish - NPHS1 gene

Nephrotic syndrome type 1 (NPHS1), also called nephrotic syndrome Finnish type, is a disorder characterized by a prenatal onset of massive proteinuria followed by a severe resistance evident steroids at birth, with rapid progression to end - stage failure renal.

The first symptom is fetal proteinuria, leading to an increase of more than 10 times the concentration of alpha-fetoprotein (AFP) in the amniotic fluid, and a parallel increase but reduced its concentration in maternal blood. This is because the fetus loses large amounts of AFP in urine due to kidney damage. Other signs and symptoms of the disease appear shortly after birth and include proteinuria, hypoalbuminemia, hyperlipidemia and edema.

This process is due to mutations in the NPHS1 gene, located on the long arm of chromosome 19 (19q13.1), which encodes the nephrin protein, which is the main component for controlling the filtration membrane and exclude albumin and other macromolecules glomerular filtration plasma and urine are not eliminated. It seems to play a role in the development or function of the glomerular filtration barrier of the kidney, regulating the glomerular vascular permeability, anchoring the membrane filtration podocytes to the actin cytoskeleton. Also involved in the formation of skeletal muscle through the regulation of myoblast fusion.

Mutations in the gene cause NPHS1 pseudocystic expansion in the proximal tubules in most cases. Mutations cause a defective intracellular transport of nephrin or result in the absence of the protein, resulting in alterations in the pores resulting in a malfunction of the membrane glomerular filtration, thus losing the selective ability. Mutations cause accumulation of type IV collagen in the renal cortex in patients with congenital nephrotic syndrome. Collagen accumulation and laminin protein are disproportionate.

This disease is inherited in an autosomal recessive pattern, that is, both copies of the gene in every cell must have mutations for alteration is expressed. The parents of an individual with an autosomal recessive disease have a copy of the mutated gene, but usually show no signs and symptoms of the disease.

Tests in IVAMI: in IVAMI perform detection of mutations associated with nephrotic syndrome type 1, by complete PCR amplification of the exons of the NPHS1 gene and subsequent sequencing.

Samples recommended: EDTA blood collected for separation of blood leukocytes, or impregnated sample card with dried blood (IVAMI may mail the card to deposit the blood sample).