The collecting tubules become cystic and the diameter of the cysts determines the size of the kidneys, which may be enlarged or small. Exploration of the renal fossa in some cases reveals no renal artery, renal vein, ureter or cysts, suggesting that renal agenesis and dysplastic kidneys may be at different ends of a spectrum of renal malformation. Prevalence Multicystic dysplastic kidney disease is found in about 1 per 1000 births. Diagnosis Ultrasonographically, the kidneys are replaced by multiple irregular cysts of variable size with intervening hyperechogenic stroma. Bilateral multicystic dysplastic kidney disease is fatal before or soon after birth, due to pulmonary hypoplasia.
Unilateral disease is associated with a normal prognosis.
III renal dysplasia is characterized by markedly enlarged irregular kidneys with innumerable cysts of variable sizes interspersed among normal or compressed renal parenchyma. Both kidneys are generally equally enlarged and only rarely is one involved so slightly that it remains of normal size. One in 1000 people carry the APKD mutant gene. Adult polycystic kidney disease is usually asymptomatic until the third or fourth decade of life, and, although histological evidence of the disease is likely to be present from intrauterine life, the age of onset of gross morphological changes that are potentially detectable by ultrasonography is uncertain. Rarely, however, kidneys that are anatomically similar may cause death in infancy or early childhood and the condition has been designated as adult variety occurring in infancy .