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Long‐term outcome and intervention of urea cycle disorders in Japan
Author(s) -
Kido Jun,
Nakamura Kimitoshi,
Mitsubuchi Hiroshi,
Ohura Toshihiro,
Takayanagi Masaki,
Matsuo Masafumi,
Yoshino Makoto,
Shigematsu Yosuke,
Yorifuji Tohru,
Kasahara Mureo,
Horikawa Reiko,
Endo Fumio
Publication year - 2012
Publication title -
journal of inherited metabolic disease
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.462
H-Index - 102
eISSN - 1573-2665
pISSN - 0141-8955
DOI - 10.1007/s10545-011-9427-0
Subject(s) - ornithine transcarbamylase deficiency , urea cycle , medicine , pediatrics , hyperammonemia , biology , arginine , biochemistry , amino acid
Urea cycle disorders (UCDs) are one of the most frequently inherited metabolic diseases in Japan, with an estimated prevalence of 1 per 50,000 live births. Here, we investigated the clinical manifestations, treatment, and prognosis of 177 patients with UCDs who were evaluated and treated from January 1999 to March 2009. These included 77 cases of neonatal‐onset UCDs and 91 cases of late‐onset UCDs. The most common UCD was ornithine transcarbamylase deficiency (OTCD), which accounted for 116 out of 177 patients. This result is similar to a previous study performed between 1978 and 1995 in Japan: OTCD accounted for about two‐thirds of the total number of UCD cases. We studied the relationship between prognosis and the peak blood ammonia level at the onset in 151 UCD patients. Compared with a previous survey conducted in Japan, we found that a greater number of patients survived without any mental retardation despite their peak blood ammonia levels being greater than 360 μmol/l. The 5‐year survival rate of patients with OTCD improved to 86% for those with the neonatal‐onset type and to 92% for those with the late‐onset type. We hypothesize that the increased survival rate is due to early diagnosis and better treatments that are now available in Japan. It is very important to diagnose and treat UCDs, especially OTCD, when the blood ammonia levels in patients are low. The outcome in patients with low blood ammonia levels was better than that in patients with high blood ammonia levels.