A deficiency of pyrimidine 5-prime nucleotidase (P5N), also called uridine 5-prime monophosphate hydrolase (UMPH1), causes congenital nonspherocytic hemolytic anemia-8 (CNSHA8), which is characterized by marked basophilic stippling and the accumulation of high concentrations of pyrimidine nucleotides within the erythrocyte. The enzyme is implicated in the anemia of lead poisoning and is possibly associated with learning difficulties. Hirono et al. (1988) suggested that this deficiency is the third most common RBC enzymopathy--after G6PD (300908) and pyruvate kinase (see 266200) deficiencies--causing hemolysis (summary by Marinaki et al., 2001). [from
OMIM]