Mongolian spots remaining in schoolchildren a statistical survey in Central Okinawa.

10,248 schoolchildren in central Okinawa were examined by one observer for remaining Mongolian spots. The spots were found in 783 schoolchildren (7.64%). Sacral Mongolian spots disappeared smoothly, while extrasacral Mongolian spots showed a general tendency toward disappearance. There were interesting but unexplainable differences in the rate of disappearance of Mongolian spots among city dwellers, suburban inhabitants and rural people in the area examined.