Four cases of bladder exstrophy in two families.

Bladder exstrophy is a rare congenital anomaly, caused by abnormal development of the cloacal membrane. To our knowledge, 18 familial patients with this malformation have been described. Two sets of familial cases with bladder exstrophy are reported here: two cousins and a mother and son and the published reports of the 18 familial cases among 682 index patients with bladder exstrophy are reviewed. Ultrasonography is advocated as the investigation of choice for early prenatal diagnosis.