Hereditary disorders of erythrocyte enzymes in non-glycolytic metabolic pathways.

A number of non-glycolytic metabolic abnormalities may occur in erythrocytes without significantly altering cell function or life span. They include deficiencies of adenine or hypoxanthine-guanine phosphoribosyltransferases, adenosine deaminase, nucleoside phosphorylase, and hyperactivity of ribosephosphate pyrophosphokinase. Three principal enzyme defects are causally associated with hemolytic anemia: hyperactive adenosine deaminase and deficiencies of adenylate kinase and pyrimidine nucleotidase. These produce hemolytic syndromes of variable severity ranging from mild or subclinical in the adenosine deaminase defect to severe in adenylate kinase deficiency. Pyrimidine nucleotidase deficiency is much more common and is associated with intermediate degrees of anemia. Acquired nucleotidase deficiency may occur secondary to lead toxicity and produces a syndrome virtually identical to the hereditary deficiency states.