ABSTRACT
Some degree of upper urinary tract duplication is found in 0.8% of postmortem examinations and in a rather higher proportion (2-3%) of patients undergoing intravenous urography (IVU) for various indications. In approximately 40% of cases the condition is bilateral. The anomaly is transmitted as an autosomal dominant trait with incomplete penetrance, so that among members of affected families the incidence is of the order of 8%.
