American Urological Association - Autosomal Recessive Polycystic Kidney Disease
Autosomal Recessive Polycystic Kidney Disease
- Most cases result in stillbirth or early neonatal death (40%); encountered in 1:20,000 live births.
- Associated with gene PKHD1 that maps to chr region 6p21-p12 and encodes for protein fibrocystin located in cilium; >300 mutations in PKHD1 identified.
- Mutations in PKHD1 are detected in 80-85% of cases.
- Enlarged cystic kidney at birth.
- Bilaterally enlarged kidneys with "radial rays" of cysts oriented perpendicular to the cortex (image A).
- Reniform shape is generally maintained.
- Ureters are normal.
- Cystic dilatation of cortical and medullary collecting ducts +/- involvement of PCT and Bowman's capsule (image B).
- Nephrons between dilated ducts are normal (vs. renal dysplasia).
- Autosomal recessive inheritance; hepatic lesions mimicking congenital hepatic fibrosis may also be present (older patients develop hepatosplenomegaly and portal hypertension).
- Lethal neonatal form: massively enlarged kidney and small hypoplastic lung.
- Infantile childhood form: smaller kidneys and larger lungs and congenital hepatic fibrosis.
- Lethal in neonates; good prognosis if neonate survives 1st month of life (90% 5 years survival).
- 50% of children will have systemic hypertension and renal insufficiency.