Histological changes in the thymus at autopsy have been considered consistent with involution rather than a congenital absence of the thymus. Inheritance and incidence This disorder has been described in at least 30 patients. The defect is inherited in an autosomal recessive manner and in many families there is evidence of consanguinity. Studies of the mutant enzyme in different families have demonstrated varying amounts of immunologically reactive protein with altered kinetic parameters, isoelectric points and electrophoretic mobility. In severe cases no uric acid is detectable in any body fluid, but significant levels have been found in late presenters.
Heterozygotes have intermediate levels but are clinically normal.
No satisfactory therapy has yet been found for the majority of these patients and the most severely affected have invariably died within the first 5 years. 1991 Molecular analysis of mutations in three patients with purine nucleoside phosphorylase deficiency. Early prenatal diagnosis of inherited severe immunodeficiencies linked to enzyme deficiencies. 1990 Importance of the human erythrocyte in the diagnosis of inherited purine and pyrimidine disorders. 1991 Analysis of purines and pyrimidines in blood, urine and other physiological fluids.