Pyrimidine 5′-Nucleotidase Deficiency: Studies of five Cases in two Japanese Families

Abstract

Two new families with red cell pyrimidine 5′-nucleotidase (P5N) deficiencies were found in Japan. The enzyme activities were 4.8% in case 1 and 9.7% in case 2. The propositi showed characteristic hemolytic anemia with marked basophilic stippling, increased reduced glutathione content and accumulation of pyrimidine nucleo-tides in the red cell.

High Michaelis constants for cytidine monophosphate, normal thermostability, abnormal optimum pH in both cases, and normal electrophoretic mobility in case 1 and slower mobility in case 2 were shown, suggesting that the cause of P5N deficiency, at least in these cases, is due to the structural gene mutation.