What Your Test Results Mean:

Carriers typically show no symptoms of congenital Finnish nephrosis; however, carriers are at an increased risk of having a child with congenital Finnish nephrosis. Risk for the current or future pregnancies is dependent on your partner’s carrier status. Carrier testing of your partner is recommended in addition to consultation with a genetic counselor for more detailed risk assessment.

Disease Explained:

Congenital Finnish nephrosis is an inherited condition that impairs the ability of the kidneys to filter protein out of the urine. This disease is usually diagnosed shortly after birth before 3 months of age. Affected infants have difficulty getting nutrients and swell with excess fluid. One of the important proteins lost in the urine of these patients is albumin. Albumin is a protein that acts like a sponge, drawing extra fluid from the body into the bloodstream where it remains until removed by the kidneys. When albumin leaks into the urine, the blood loses its capacity to absorb extra fluid from the body, causing edema. They also have compromised immune systems and are prone to infections. Congenital Finnish nephrosis is often fatal in infancy or early childhood; however, kidney transplant is curative. Without a transplant, affected individuals die by 5 years of age, but a successful transplant can allow for a normal lifespan.

How the Genetics Works:

Congenital Finnish nephrosis is an autosomal recessive condition caused by pathogenic variants in the NPHS1 gene. In general, individuals have two copies of the NPHS1 gene. Carriers of congenital Finnish nephrosis have a single variant in one copy of the NPHS1 gene while individuals with congenital Finnish nephrosis have variants in both copies of their genes, one inherited from each parent. Risk for two carriers to have a child with the disorder is 25%.