New Variant of Purine Nucleoside Phosphorylase Deficiency with Predominant Neurological Phenotype

Background/Purpose: Purine Nucleoside Phosphorylase Deficiency is a rare disorder of purine metabolism leading to severely impaired immune function with recurrent infections, autoimmunity and malignancy. To date fewer than seventy cases have been reported worldwide. Although there is some variability in susceptibility to infection ranging from severe combined immunodeficiency (SCID) to recurrent infections immunological involvement is regarded as a hallmark of the disease.

Methods: We present a 14 years old girl of consanguineous arabic parents displaying a predominant neurological phenotype combining loss of motor functions, oculomotor apraxia, progressive upper and lower limb spasticity and action induced choreoathetosis. Her laboratory findings (low plasma urea acid, zero PNP-Activity in erythrocytes) indicated into the direction of purine nucleoside phosphorylase deficiency (PNP) deficiency which could finally be confirmed genetically.

Conclusion: Our case demonstrates a new variant of the disease resulting in a severe neurological phenotype combining spasticity and athetosis rather than immunodeficiency. Further studies are needed to assess whether on the DNA or RNA level some kind of restoration of immune function.