Dihydropyrimidinuria: The First Case in Japan

Abstract

Dihydropyrimidinuria (McKusick 222748) is a recently described disorder of pyrimidine metabolism that presents neurological symptoms different in degree. Only two cases have been reported to date (Duran et al, 1991; Henderson et al, 1993). The patients with dihydropyrimidinuria excrete large amount of dihydrouracil and dihydrothymine, and moderate amount of uracil and thymine in urine. Therefore this disease is thought to be caused by a deficiency of dihydropyrimidine amidohydrolase (DHPase; EC 3.5.2.2), the second step of pyrimidine base catabolism. The first case, reported by Duran et al (1991), was hospitalized for convulsion and disturbed consciousness at the age of 8 weeks, but whose subsequent development had been normal. The second case reported by Henderson et al (1993) presented severe developmental delay. These two patients were discovered by the urinary gas chromatography mass spectrometry (GC-MS) analysis for the neurological sick children. We report here another case of dihydropyrimidinuria which is the first case in Japan and probably the third worldwide. We discovered her by using high-performance liquid chromatography (HPLC) at the mass screening program.