- 著者
- 
             
             Ryohei Norioka
             
             Shinsuke Tobisawa
             
             Ryusei Nishigori
             
             Tomiko Kuhara
             
             Masahide Yazaki
             
             Masayoshi Nagao
             
             Toshihiro Ohura
             
             Yasuyuki Takai
             
             Asuka Funai
             
             Kazuhito Miyamoto
             
             Akihiro Kawata
             
             Kazushi Takahashi
             
          
- 出版者
- International Research and Cooperation Association for Bio & Socio-Sciences Advancement
- 雑誌
- Intractable & Rare Diseases Research (ISSN:21863644)
- 巻号頁・発行日
- vol.10, no.2, pp.126-130, 2021-05-31 (Released:2021-06-03)
- 参考文献数
- 16
- 被引用文献数
- 
             
             
             3
             
             
          
        
        We report a case of saccharopinuria with hyperammonemia and hypercitrullinemia in a Japanese woman who presented with elderly-onset epilepsy, progressive cognitive decline, and gait ataxia. Blood amino acid analysis revealed an increase in citrulline, cystine, and lysine levels, and urine amino acid analysis showed increased citrulline and cystine levels. Urine metabolomics revealed an increased saccharopine level, leading to the definitive diagnosis of saccharopinuria. In western blots of liver biopsy samples, normal citrin levels were observed, suggesting that adult-onset citrullinemia type 2 (CTLN2) was not present. In addition, decreased argininosuccinate synthetase (ASS) levels were observed, and ASS1 gene, a causative gene for citrullinemia type 1 (CTLN1), was analyzed, but no gene mutations were found. Because the causes of hypercitrullinemia were not clear, it might be secondary to saccharopinuria. Muscle biopsy findings of the biceps brachii revealed diminished cytochrome c oxidase (COX) activity, mitochondrial abnormalities on electron microscopy and p62-positive structures in immunohistochemical analyses. Saccharopinuria is generally considered a benign metabolic variant, but our case showed elevated lysine and saccharopine levels causing ornithine circuit damage, mitochondrial dysfunction, and autophagy disorders. This may lead to so far unknown neurological disorders.