Asthma Allergy Immunology

Asthma Allergy Immunology

Purine Nucleoside Phosphorylase Deficiency Presenting with Neurological Involvement: A Case Report of Two Siblings

Demet TEKCAN 1, Ilknur KULHAS CELIK 1, Teresa K. TARRANT 2, Michael S. HERSFIELD 2-3, Hasibe ARTAC 1,

1 Division of Pediatric Immunology and Allergy, Selcuk University School of Medicine, Konya, Türkiye
2 Department of Medicine, Division of Rheumatology and Immunology, Duke University School of Medicine, Durham, USA
3 Department of Biochemistry, Duke University School of Medicine, Durham, USA

DOI: 10.21911/aai.2024.535
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Purine nucleoside phosphorylase (PNP) deficiency is a rare immunodeficiency syndrome generally characterized by profound T cell deficiency and variable B cell function. More than half of PNP-deficient patients present with neurological dysfunction, with manifestations such as mental and motor retardation, spasticity, hypertonia, ataxia, and behavioral disturbances.

Here, we report two siblings diagnosed with PNP deficiency in early infancy. Our patients had developmental delays, and their immunological findings indicated T-B+NK+ leaky/atypical severe combined immune deficiency. The patients are being treated with regular intravenous immunoglobulin replacement, as well as trimethoprim-sulfomethoxazole and fluconazole, for prophylaxis in preparation for transplantation.

These cases draw attention to the possibility of primary immune deficiency in patients with recurrent infections and lymphopenia. In addition, PNP deficiency should be kept in mind in the presence of developmental delay, low uric acid levels, and lymphopenia.

Keywords : Combined immune deficiency, development delay, purine nucleoside phosphorylase deficiency, lymphopenia