Medullary cystic disease

Alternative names:

familial juvenile nephrophthisis; Senior-Loken syndrome

Definition:

A hereditary kidney disorder characterized by gradual and progressive loss of kidney function because of cysts in the kidney medulla (center).

Causes, incidence, and risk factors:

Medullary cystic disease is a disorder involving the formation of cysts in the kidney medulla. The condition is inherited in most cases. The disorder causes an inability to concentrate the urine. This results in excessive fluid loss from the body, which is accompanied by loss of sodium. This is a "high output" type of chronic renal failure (renal failure with increased urine volume, but with all other aspects of kidney function decreased).

The disorder is rare, occurring in about 3 out of 100,000 people, mostly those under age 40. The disorder runs in families, and the inheritance patterns vary. (There is X-linked and autosomal dominant inheritance in different families. X-linked inheritance is carried on the X chromosome and is expressed in males that inherit the faulty gene from their mother and females that inherit the faulty gene from both parents. Females that only inherit the gene from one parent will not develop the disorder but can pass it on to their children. With autosomal dominance, if one parent has the gene for the disorder, 50% of the children will display symptoms). Risk factors include an individual or family history of medullary cystic disease, chronic renal failure, or increased urinary volume with excessive thirst.