153 ERYTHROCYTE ADENINE PRPP AVAILABILITY IN TOO TYPES OF APRT DEFICIENCY USING SILICON OIL METHOD

Abstract

For the cause of 2, 8-dihydroxyadenine urolithiasis. Japanese type adenine phosnhorobosyltransferase (APRT) deficiency is common in Japan. Some homozygotes for the Japanese type APRT deficiency had no urolithiasis and were clinically healthy. APRT activity in erythrocyte from homozygotes of Japanese type APRT deficiency was at the same levels as the activity from the healthy heterozygotes for the complete APRT deficiency. For the diagnosis of Japanese type APRT deficiency we compared the erythrocyte adenine phosnhoribosylpyrophosphate (PRPP) availability of Japanese type APRT deficiency with complete APRT deficiency using silicon oil method. Homozygote of Japanese type APRT deficiency showed 4.3±2.7% (mean ± standerd deviation) of adenine PRPP availability and every patient showed the almost same PRPP availability. Heterozygote showed 86.0±6.0% of adenine PRPP availability in comparing to those of normal subjects. These results supported the same mutation in Japanese type APRT gene. While in a Japanese family of complete ARRT deficiency, adenine PRPP availability of homozygote vias undetectable and that of heterozygote was normal low (54.3% of mean normal activity). The adenine PRPP availability of heterozygote of complete APRT deficiency was diagnostically different from that of homozygote of Japanese type APRT deficiency.