RESUMEN
The enzyme inosine triphosphate pyrophosphatase (ITPase) catalyses the pyrophosphohydrolysis of ITP to IMP. ITPase deficiency is a clinically benign autosomal recessive condition characterised by the abnormal accumulation of ITP in erythrocytes. A deficiency of ITPase may predict adverse reactions to therapy with the thiopurine drug 6-mercaptopurine and its prodrug azathioprine. In this study, we examine the frequencies of ITPA polymorphisms in 100 healthy Japanese individuals. The allele frequency of the 94C > A variant in the Japanese sample was 0.135 (Caucasian allele frequency 0.06). The IV2 + 21A > C polymorphism was not found in Japanese (Caucasian allele frequency 0.130). Allele frequencies of the 138G > A, 561G > A and 708G > A polymorphisms were 0.57, 0.18 and 0.06 respectively in the Japanese population, and with the exception of the 138G > A polymorphism, similar to allele frequencies in Caucasians.
Asunto(s)
Alelos , Polimorfismo Genético , Pirofosfatasas/genética , Antimetabolitos/uso terapéutico , Pueblo Asiatico , Azatioprina/uso terapéutico , Eritrocitos/enzimología , Frecuencia de los Genes , Genes Recesivos , Variación Genética , Humanos , Hidrólisis , Japón , Mercaptopurina/uso terapéutico , Inhibidores de la Síntesis del Ácido Nucleico/uso terapéutico , Polimorfismo de Nucleótido Simple , Población Blanca , Inosina TrifosfatasaRESUMEN
Inosine triphosphate pyrophosphohydrolase (ITPase) deficiency is characterized by abnormal accumulation of inosine triphosphate. We describe the first Japanese case with ITPase deficiency and demonstrate that the deficiency of ITPase activity is not only found in erythrocytes but also in white blood cells.
Asunto(s)
Leucocitos/enzimología , Errores Innatos del Metabolismo/metabolismo , Pirofosfatasas/deficiencia , Adulto , Eritrocitos/enzimología , Femenino , Humanos , Inosina Trifosfato/metabolismo , Japón , Inosina TrifosfatasaRESUMEN
We performed allopurinol challenge tests to evaluate the metabolic state of a citrullinaemic patient who received a living-relative donor liver transplant. Before transplantation, large amounts of orotic acid and orotidine were excreted during the challenge test. Following transplantation, excretion of these compounds in response to allopurinol was normalised. The challenge test was a safe and useful method to evaluate the metabolic state of the patient.