High prevalence of ectopic kidney in Coast Province, Kenya

To establish the prevalence of congenital urinary tract abnormalities in a full population-based ultrasound survey of an area of coastal Kenya.

Ultrasound examination of 3118 residents of 912 households, including all available subjects over 2 years of age, residing in five contiguous rural villages 50 km south of Mombasa.

Survey findings indicated simple renal ectopia in 11 of 3118 subjects (0.35%) and renal agenesis in three (0.096%). No cases of horseshoe kidney or complex urinary anomaly were detected, and no cases of multiple congenital anomaly were found. Ectopia cases were evenly distributed between men and women, and across the five study villages. None of the individuals affected by renal ectopia were closely related (i.e. <5th-degree relations).

There is an unusually high prevalence of ectopia among unrelated subjects in this area. In this setting, the findings suggest either a common exposure to teratogenetic factors, or a hereditary condition with variable penetrance, where more severely affected individuals are not observed because of foetal/infant mortality.