First Case of Argininosuccinic Aciduria in Japan : Clinical Observations and Treatment

Abstract

Argininosuccinic aciduria is the most common disorder of the urea cycle in European countries and the U.S.A., but no case has ever been reported in Japan. It is caused by the deficiency of the enzyme L-argininosuccinic acid lyase (EC 4. 3. 2. 1., ASA lyse) with aresulting accumulation of large amounts of argininosuccinic acid (ASA) in body fluids. It is divided into three clinical types¹: neonatal, subacute and late-onset form accompanied with mental retardation, hepatomegaly and friable hair, known as trichorrhexis nodosa. Genetic heterogeneity with the various clinical manifestations has been reported with the suggestion²’³ of different biochemical forms in argininosuccinic aciduria. We report here the first case of argininosuccinic aciduria in Japan and the follow-up study under the treatment with 1-arginine supplemented protein restricted diet for two and a half years.