A Japanese case with inosine triphosphate pyrophosphohydrolase deficiency attributable to an enzymatic defect in white blood cells.

Inosine triphosphate pyrophosphohydrolase (ITPase) deficiency is characterized by abnormal accumulation of inosine triphosphate. We describe the first Japanese case with ITPase deficiency and demonstrate that the deficiency of ITPase activity is not only found in erythrocytes but also in white blood cells.