Red cell uridine monophosphate kinase polymorphism in Japanese

Samples from 635 unrelated Japanese blood doners in Tokyo were examined for their red cell uridine monophosphate kinase phenotypes using starch gel electrophoresis. Three phenotypes were found: UMPK1 (570, 89.76%), UMPK 2--1 (63, 9.92%) and UMPK 2 (2, 0.32%). The corresponding gene frequency for UMPK1 was 0.9472 and for UMPK2 was 0.0528. The UMPK2 frequency in the present study was slightly higher than the previously reported value for Caucasians in the United States, but the difference is not statistically significant. A study of 15 twin pairs and their parents was in agreement with the hypothesis of autosomal codominant inheritance for UMPK.