Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0025362 (mental retardation)
 15,878 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Hyperornithinemia, hyperammonemia and homocitrullinuria (HHH) syndrome presents with various neurological symptoms, including mental retardation, spastic paraparesis with pyramidal signs, cerebellar ataxia, and episodic disturbance of consciousness or coma caused by hyperammonemia. We report three novel mutations in the mitochondrial ornithine transporter gene (ORNT1) of Japanese patients with HHH syndrome: a nonsense mutation (R179X) associated with exon skipping and a frameshift, a missense mutation (G27E), and an insertion of AAC between codons 228 and 229, leading to an insertion of the amino acid Asn. The ORNT1 gene consists of at least six exons, and all exon-intron junction sequences conform to the GT/AG rule. All 3 patients were homozygous for their respective mutations. This study confirms that defects in the ORNT1 gene cause the HHH syndrome and that the genetic basis in Japanese patients is heterogeneous.
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PMID:Three novel mutations (G27E, insAAC, R179X) in the ORNT1 gene of Japanese patients with hyperornithinemia, hyperammonemia, and homocitrullinuria syndrome. 1080 33

Patients with mitochondrial ornithine transporter deficiency (or HHH syndrome) present with various neurological symptoms, including mental retardation, spastic paraparesis with pyramidal signs, cerebellar ataxia, and episodic disturbance of consciousness or coma due to hyperammonemia. We previously described three novel mutations in the ORNT1 gene in Japanese patients with HHH syndrome. In this article, we report a new patient with HHH syndrome, a 52-year-old woman, who had the typical clinical features, except for an absence of mental retardation. When we screened this patient, as well as a previously described Japanese patient, for mutations in the ORNT1 gene, we found that both were homozygous for a nonsense mutation (R179X). Furthermore, reverse transcription (RT)-polymerase chain reaction (PCR) of fibroblast RNA from one patient showed exon 4 skipping, as had been observed in a previously reported patient with R179X. These results, together with the findings in our previous report, show that, in three of our five reported Japanese HHH patients (six of ten alleles), R179X is present, suggesting that this is a common mutation in Japanese patients with HHH syndrome.
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PMID:Diagnosis of Japanese patients with HHH syndrome by molecular genetic analysis: a common mutation, R179X. 1135 15

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.
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PMID:[Molecular genetic studies of mitochondrial ornithine transporter deficiency (HHH syndrome)]. 1171 19

Mitochondrial ornithine transporter deficiency, or HHH syndrome, is a metabolic disorder resulting in various neurologic symptoms, including mental retardation, spastic paraparesis with pyramidal signs, cerebellar ataxia, and episodic disturbance of consciousness or coma caused by hyperammonemia. Several mutations have been reported in the ORNT1 gene encoding mitochondrial ornithine transporter of patients with this disorder. In this article, we report a new patient, a male 15 years of age, who had typical clinical features of HHH syndrome. Because the patient did not have any of the three mutations previously described in other Japanese patients with HHH syndrome, and the only material available from the patient was peripheral leukocytes, we established a genomic polymerase chain reaction method using intronic primers to amplify every exon of the ORNT1 gene, and we directly sequenced the polymerase chain reaction products. Using this method, we documented a novel mutation in this patient, P126R, and demonstrated that HHH syndrome is genetically heterogeneous, even in the Japanese population.
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PMID:A novel mutation, P126R, in a Japanese patient with HHH syndrome. 1181 39