APRT is ubiquitously distributed in all human cells, with the highest concentration in nucleated cells. However, the clinical spectrum is broad, and while the defect may be life-threatening and can present from birth, it may also be benign, presenting as late as the seventh decade.
Some few cases remain completely asymptomatic and are only detected during family studies.
These include fever from urinary tract infection, macroscopic haematuria, crystalluria, dysuria, urinary retention and abdominal colic. Purine production and excretion is otherwise normal, as are the general biochemistry, other purine enzymes and immunology. The occurrence of spontaneous abortions in one family may represent expression of the defect in utero. The defect shows an autosomal recessive mode of inheritance. The Type I disorder has been reported in 51 caucasian families and in 30 kindreds in Japan.