Autosomal-Recessive (Infantile) Polycystic Kidney Disease
Infantile polycystic kidney disease is an autosomal-recessive disorder.
It occurs in 1:6000–1:14,000 live births.
It affects both children and adults.
Slight male predominance is reported (male-to-female ratio 2:1).
The kidneys are bilaterally involved.
For patients who survive infancy, approximately 50% require dialysis by age 20 due to renal failure.
Children develop arterial hypertension and end-stage renal failure. Hepatic fibrosis and biliary dysgenesis are frequent. Approximately one third die of lung hypoplasia. No association with renal neoplasms has been documented.
In this condition, the kidneys are symmetrically enlarged and retain a reniform configuration and appear diffusely sponge on section. The parenchyma exhibits cylindrical dilated collecting ducts radiating from the medulla to the cortex, their long axis perpendicular to the renal surface, obscuring the cortical-medullary junction.
In the younger patients, the kidney is almost entirely made up of dilated terminal branches of the collecting ducts, cylindrical in the cortex and round to oval in the medulla, lined with cuboidal epithelium sometimes with foci of hyperplasia. In the older patients, the cysts are fewer in number but larger, associated with tubular atrophy and glomerular sclerosis of the surrounded parenchyma.
Autosomal-recessive polycystic kidney disease is linked to a gene mapped on chromosome 6p,28 named polycystic kidney and hepatic disease gene (PKHD1) due to the consistent hepatic involvement.
Autosomal-recessive polycystic kidney should be distinguished from multicystic renal dysplasia.