American Urological Association - Autosomal Recessive Polycystic Kidney Disease


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Autosomal Recessive Polycystic Kidney Disease

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  • 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.
  • Gross:
    • Bilaterally enlarged kidneys with "radial rays" of cysts oriented perpendicular to the cortex (image A).
    • Reniform shape is generally maintained.
    • Ureters are normal.
  • Histology:
    • 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.