同: hyperammonemia-hyperornithinemia- homocitrullinemia

WordNet

a pattern of symptoms indicative of some disease
a complex of concurrent things; "every word has a syndrome of meanings"
the 8th letter of the Roman alphabet (同)h

PrepTutorEJDIC

(疾患の徴候となる一群の)症徴候,症候群 / (事件・社会的状態などのパターンを示す)徴候形態
hydrogenの化学記号
鉛筆の硬度 / 《俗》heroin

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出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2016/12/13 13:26:45」(JST)

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Ornithine translocase deficiency, also called hyperornithinemia-hyperammonemia-homocitrullinuria (HHH) syndrome,^[1] is a rare autosomal recessive^[2] urea cycle disorder affecting the enzyme ornithine translocase, which causes ammonia to accumulate in the blood, a condition called hyperammonemia.

Ammonia, which is formed when proteins are broken down in the body, is toxic if the levels become too high. The nervous system is especially sensitive to the effects of excess ammonia.

Pathophysiology

Ornithine translocase deficiency has an autosomal recessive pattern of inheritance.

Mutations in the SLC25A15 gene cause ornithine translocase deficiency. Ornithine translocase deficiency belongs to a class of metabolic disorders referred to as urea cycle disorders. The urea cycle is a sequence of reactions that occurs in liver cells. This cycle processes excess nitrogen, generated when protein is used by the body, to make a compound called urea that is excreted by the kidneys. The SLC25A15 gene provides instructions for making a protein called a mitochondrial ornithine transporter. This protein is needed to move a molecule called ornithine within the mitochondria (the energy-producing centers in cells). Specifically, this protein transports ornithine across the inner membrane of mitochondria to the region called the mitochondrial matrix, where it participates in the urea cycle. Mutations in the SLC25A15 gene result in a mitochondrial ornithine transporter that is unstable or the wrong shape, and which cannot bring ornithine to the mitochondrial matrix. This failure of ornithine transport causes an interruption of the urea cycle and the accumulation of ammonia, resulting in the signs and symptoms of ornithine translocase deficiency.

This disorder is inherited in an autosomal recessive pattern, which means the defective gene is located on an autosome, and two copies of the gene - one from each parent - are required to be born with the disorder. The parents of an individual with an autosomal recessive disorder each carry one copy of the altered gene but do not show signs and symptoms of the disorder.

External links

Ornithine translocase deficiency at NLM Genetics Home Reference
For a thorough scientific overview of hyperornithinemias, one can consult chapter 83 of The Online Metabolic and Molecular Bases of Inherited Disease.^[3]

References

^ Online Mendelian Inheritance in Man (OMIM) 238970
^ Hommes FA, Roesel RA, Metoki K, Hartlage PL, Dyken PR (Feb 1986). "Studies on a case of HHH-syndrome (hyperammonemia, hyperornithinemia, homocitrullinuria)". Neuropediatrics. 17 (1): 48–52. doi:10.1055/s-2008-1052499. ISSN 0174-304X. PMID 3960284.
^ Charles Scriver, Beaudet, A.L., Valle, D., Sly, W.S., Vogelstein, B., Childs, B., Kinzler, K.W. (Accessed 2007). New York: McGraw-Hill. - Summaries of 255 chapters, full text through many universities. There is also the OMMBID blog.

UpToDate Contents

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1. 尿素サイクル障害：臨床的特徴および診断 urea cycle disorders clinical features and diagnosis

English Journal

Improving long term outcomes in urea cycle disorders-report from the Urea Cycle Disorders Consortium.

Waisbren SE1, Gropman AL2; Members of the Urea Cycle Disorders Consortium (UCDC), Batshaw ML3.
Journal of inherited metabolic disease.J Inherit Metab Dis.2016 May 23. [Epub ahead of print]
The Urea Cycle Disorders Consortium (UCDC) has conducted, beginning in 2006, a longitudinal study (LS) of eight enzyme deficiencies/transporter defects associated with the urea cycle. These include N-acetylglutamate synthase deficiency (NAGSD); Carbamyl phosphate synthetase 1 deficiency (CPS1D); Orn
PMID 27215558

Ornithine and Homocitrulline Impair Mitochondrial Function, Decrease Antioxidant Defenses and Induce Cell Death in Menadione-Stressed Rat Cortical Astrocytes: Potential Mechanisms of Neurological Dysfunction in HHH Syndrome.

Zanatta Â1, Rodrigues MD1, Amaral AU1, Souza DG1, Quincozes-Santos A1, Wajner M2,3.
Neurochemical research.Neurochem Res.2016 May 9. [Epub ahead of print]
Hyperornithinemia-hyperammonemia-homocitrullinuria (HHH) syndrome is caused by deficiency of ornithine translocase leading to predominant tissue accumulation and high urinary excretion of ornithine (Orn), homocitrulline (Hcit) and ammonia. Although affected patients commonly present neurological dys
PMID 27161368

Heterologous Expression in Yeast of Human Ornithine Carriers ORNT1 and ORNT2 and of ORNT1 Alleles Implicated in HHH Syndrome in Humans.

Doimo M1,2, Lopreiato R3, Basso V1,2, Bortolotto R1,2, Tessa A4, Santorelli FM4, Trevisson E1,2, Salviati L5,6.
JIMD reports.JIMD Rep.2015 Nov 21. [Epub ahead of print]
Hyperornithinemia-hyperammonemia-homocitrullinuria (HHH) syndrome is an autosomal recessive metabolic disorder usually presenting in the neonatal period with intermittent episodes of hyperammonemia, psychomotor delay, and progressive encephalopathy. Adult cases usually evolve into frank spastic para
PMID 26589310