Dysequilibrium/ataxic diplegia with immunodeficiency.

A girl with purine nucleoside phosphorylase (PNP) deficiency is described. The nature of the motor disorder is similar to other children since found to have PNP deficiency. It is suggested that the diagnosis be considered in any child with unexplained dysequilibrium/ataxic diplegia. Other previously unreported features are intracytoplasmic neutrophil inclusion bodies and an improvement in the neutropenia after intravenous immunoglobulin.