ADENINE PHOSPHORIBOSYLTRANSFERASE DEFICIENCY IDENTIFIED BY URINARY SEDIMENT ANALYSIS - CELLULAR AND MOLECULAR CONFIRMATION

Adenine phosphoribosyltransferase deficiency is an autosomal recessive purine enzyme defect that causes urolithiasis and, in severe cases, r enal failure. Most homozygotes with this disorder were identified by a nalyses of excreted or surgically removed urinary stones, but some wer e identified only because they were family members of symptomatic indi viduals. We report here the detection of adenine phosphoribosyltransfe rase deficiency in two cases by routine analysis of urinary sediments. 2,8-Dihydroxyadenine-like spherical crystals were observed in the uri nary sediment, and a diagnosis of homozygous adenine phosphoribosyltra nsferase deficiency was confirmed by cellular and molecular methods. A molecular diagnostic system using the polymerase-chain reaction and s ingle-strand conformational polymorphism analysis proved to be a rapid and sensitive method to identify the APRTJ allele, a common mutant a llele among the Japanese people, These methods will facilitate identif ication of symptomatic and asymptomatic individuals with homozygous ad enine phosphoribosyl-transferase deficiency.