Congenital nephrotic syndrome

Congenital nephrotic syndrome is an inherited disorder characterized by protein in the urine and swelling of the body.

Causes
Congenital nephrotic syndrome is a very rare form of nephrotic syndrome. It occurs predominantly in families of Finnish origin and manifests shortly after birth. It is an inherited disorder. The condition is caused by a defect in the protein nephrin, which is found in the kidney.

Proteins and fats are excreted in the urine, and there is an abnormally high fat level in the blood. Swelling occurs due to kidney failure, combined with the loss of blood protein. This is because proteins in the blood normally keep fluids in the blood stream, and when protein level is low, the fluid can leak into the body tissues.

Some of the proteins lost in the urine are immune system antibodies that fight infections. The disorder commonly results in infection, malnutrition, and kidney failure. It can often lead to death by 5 years of age.

Symptoms

 * Low birth weight
 * Large placenta
 * Swelling (total body)
 * Decreased urine output
 * Foamy appearance of urine
 * Poor appetite
 * Cough

Diagnosis
An examination reveals massive fluid retention and generalized swelling. Abnormal sounds are heard when listening to the heart and lungs with a stethoscope. Blood pressure may be high. The patient may have signs of malnutrition.

A urinalysis reveals large amounts of protein and the presence of fat in the urine. Total protein in the blood may be low. The disorder can be screened for during pregnancy by finding elevated levels of alpha-fetoprotein on a routine sampling of amniotic fluid. Genetic tests should be used to confirm the diagnosis, if the screening test is positive.

CNF is one of the Finnish heritage diseases. By use of positional cloning strategies, Kestila et al. isolated the gene responsible for NPHS1. Mutations in Finnish patients with NPHS1 were found in this gene, which they termed nephrin. The most common Finnish mutation was a deletion of 2 nucleotides in exon 2 (602716.0001), resulting in a frameshift and a truncated protein. The predicted nephrin protein belongs to the immunoglobulin family of cell adhesion molecules and is specifically expressed in renal glomeruli. It was also observed that, in most cases, alleles typically found on CNF chromosomes of Finnish families were also found on CNF chromosomes of non-Finnish families from North America and Europe.

Frequent infections may occur over the course of the disease.

Treatment
Early and aggressive treatment is required to control the disorder. Diuretic medications help rid the body of excess fluid. ACE inhibitor medications (like Captopril and others) and non-steroidal anti-inflammatory drugs (like indomethacin) are used to slow the spilling of protein in the urine. Antibiotics may be needed to control infections.

Dietary modifications may include the restriction of sodium and use of dietary supplements as appropriate for the nature and extent of malnutrition. Fluids may be restricted to help control swelling.

Removal of the kidneys, dialysis, and kidney transplant may be recommended.

Prognosis
Many cases are fatal within the first year. Congenital nephrotic syndrome may be successfully controlled in some cases with early and aggressive treatment, including early kidney transplantation.

Complications

 * Frequent, severe infections
 * Malnutrition and related diseases
 * Blood clots
 * Acute kidney failure
 * Chronic kidney failure
 * End-stage kidney disease