Recurrent infections, neurologic signs, low serum uric acid levels, and lymphopenia in childhood: Purine nucleoside phosphorylase deficiency, an emergency for infants.

Purine nucleoside phosphorylase deficiency is one of the severe combined immunodeficiencies, which often clinically manifests with recurrent infections, neurologic symptoms and autoimmune diseases, and leads to thymocyte development and peripheral T cell activation defects. It is an immunologic emergency for childhood. In this case series, four cases with purine nucleoside phosphorylase deficiency were evaluated. Recurrent febrile infections and neuromotor developmental retardation were among the presenting symptoms in all cases. Absolute lymphocyte counts and serum uric acid levels were very low, and serum immunoglobulin levels were normal or slightly lower in all cases. The genetic molecular analysis of four patients revealed three predefined mutations in the purine nucleoside phosphorylase gene. Three of the four patients were lost due to sepsis during follow-up, and one patient was lost due to veno-occlusive disease in the post-hematopoietic stem cell transplantation period. We presented these cases to emphasize that purine nucleoside phosphorylase deficiency should always be considered in patients with frequent recurrent infections, neurologic findings, low serum uric acid levels, and lymphopenia.