title: [Molecular genetic studies of mitochondrial ornithine transporter deficiency (HHH syndrome)].
abstract: Mitochondrial ornithine transporter deficiency has been called HHH syndrome, because this disorder is characterized by three biochemical abnormalities; hyperornithinemia, hyperammonemia, and homocitrullinuria, and presents with various neurological symptoms; mental retardation, spastic paraparesis with pyramidal signs, cerebellar ataxia and episodic disturbance of consciousness or coma due to hyperammonemia. We identified four mutations in the mitochondrial ornithine transporter gene (ORNT1) of Japanese patients with HHH syndrome. These include a nonsense mutation (R179X), associated with exon skipping, missense mutations (G27E, P126R), and an insertion of AAC between codons 228 and 229, leading to an insertion of amino acid Asn. Especially, R179X was detected 4 of 7 Japanese patients (8 of 14 alleles), implying that this is a common mutation in Japanese population.
authors.affiliation: Department of Inherited Metabolic Disease, National Institute of Neuroscience, National Center of Neurology and Psychiatry.
authors.forename: S
authors.initials: S
authors.lastname: Tsujino
authors.forename: T
authors.initials: T
authors.lastname: Miyamoto
authors.forename: N
authors.initials: N
authors.lastname: Kanazawa
mesh_terms: D026923:Amino Acid Transport Systems, Basic; D000641:Ammonia / Q000097:blood*; D000818:Animals; D001483:Base Sequence; D002352:Carrier Proteins / Q000235:genetics*; D002956:Citrulline / Q000652:urine*; D006801:Humans; D026901:Membrane Transport Proteins; D008928:Mitochondria / Q000235:genetics*; D008969:Molecular Sequence Data; D009154:Mutation; D009422:Nervous System Diseases; D009952:Ornithine / Q000097:blood*; D013577:Syndrome
chemical_list: D026923:Amino Acid Transport Systems, Basic; D002352:Carrier Proteins; D026901:Membrane Transport Proteins; C488998:SLC25A2 protein, human; C041356:ornithine transporter; D002956:Citrulline; D000641:Ammonia; D009952:Ornithine