Here is a cut section of a kidney with autosomal recessive polycystic kidney disease (ARPKD). Note that the cysts are fairly small but uniformly distributed throughout the parenchyma so that the disease is usually symmetrical in appearance, with both kidneys markedly enlarged. The recurrence risk for this disease is, of course, 25% because of the autosomal recessive inheritance pattern. Affected babies usually do not survive long. This disorder is linked to an abnormal fibrocystin protein produced by the PKHD1 gene.

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