Purine nucleoside phosphorylase deficiency with fatal course in two sisters

Purine nucleoside phosphorylase (PNP) deficiency is a rare combined immunodeficiency disorder presenting with clinically recurrent infections, failure to thrive, various neurological disorders, malignancies, and autoimmune diseases. Here, we report two sisters with a fatal course of PNP deficiency due to delay in diagnosis. The first patient developed a liver abscess by Aspergillus fumigatus and the second patient developed Mycobacterium tuberculosis complex lymphadenitis and probable pulmonary tuberculosis due to disseminated BCG infection. The patients also suffered from sclerosing cholangitis. Mutation analysis of the PNP gene from both sisters revealed a homozygous mutation for a G>A at nucleotide 349 (349 G>A transition), which changes alanine 117 to theronine in exon 4 (A117T). An increased awareness of early signs, symptoms, and abnormal laboratory findings of PNP deficiency will establish the early prognosis and treatment.