sentences:  lupus erythematosus, autoimmune hemolytic anemia, and idiopathic thrombocytopenic purpura have been reported with PNP-deficiency.Neurological symptoms, such as developmental decline, hypotonia, and mental retardation have also been reported.The disorder is caused by a mutation of the purine nucleoside phosphorylase (PNP) gene, located at chromosome 14q13.1.