Characterization of an adenine phosphoribosyltransferase deficiency.

A case of adenine phosphoribosyltransferase deficiency in a 4.5-yr-old boy is described. A pedigree of the family, enzyme activities and kinetic data of the enzyme in the propositus and the carriers of the defect are presented. The amount of enzyme in the patient was about 2% of that in healthy subjects and correlated well with the amount of immunoreactive protein. Our data indicate that the patient's enzyme is not affected in its catalytic properties, but is made in far reduced amounts.