Juvenile nephronophthisis


Juvenile nephronophthisis is the juvenile form of nephronophthisis that causes end stage kidney disease around the age of 13; infantile nephronophthisis and adolescent nephronophthisis cause ESKD around the ages of 1 and 19, respectively.

Signs and symptoms

Typically, the signs and symptoms of juvenile nephronophthisis are limited to the kidneys. They include polyuria, polydipsia, weakness, and fatigue.
Anemia, growth retardation, no hypertension. Proteinuria and hematuria are usually absent. Polyuria is resistant to vasopressin.
When other organ systems are affected, symptoms can include situs inversus, heart abnormalities, and liver fibrosis. Juvenile nephronophthisis can also be associated with other rare disorders, including Senior–Løken syndrome and Joubert syndrome.

Pathophysiology

Juvenile nephronophthisis causes fibrosis and scarring of the kidneys, which accounts for the symptoms observed. The kidneys also often have corticomedullary cysts.
It is an autosomal recessive disease.
Ultrasonography shows bilateral small kidneys with loss of corticomedullary junction and multiple cysts only in the medulla. Cysts may only be seen if they are large enough, they are rarely visible early in disease.
Patients with medullary cystic disease present with similar features as juvenile nephronophthisis but they can be differentiated by:
  1. Absence of growth retardation.
  2. Age of presentation is third or fourth decade.
  3. Hypertension may occur.
In polycystic kidney disease, there is bilateral enlargement of kidneys.

Treatment

Epidemiology

It is the most common genetic cause of end stage kidney disease in childhood and adolescence.