Biomaterial Database

Hyperammonemia caused by impaired mitochondrial ornithine transport in a patient with partial quantitative deficiency of ornithine carbamoyltransferase. 1990

T Kuno, and S Miyazaki, and I Inoue, and T Saheki

Department of Pediatrics, Saga Medical School, Japan.

Late-onset hyperammonemia was observed in a male patient with partial quantitative deficiency of ornithine carbamoyltransferase (OCT). His liver contained 10% of the normal level of OCT, but with normal kinetics. This reduced enzyme activity alone, however, could not explain the hyperammonemia. Therefore, the effects of impaired ornithine transport into mitochondria, which seemed to be a possible precipitating factor, were examined by numerical simulation of the urea cycle. The results were as follows: (a) On the assumption that the ornithine concentrations in the cytosol and mitochondrial matrix were always equal, the ammonia handling efficiency would be unchanged by decrease in the OCT concentration to 10% of normal; (b) Under conditions of impaired mitochondrial ornithine transport that had no effects on ureagenesis with a normal amount of enzyme, 10% of the normal concentration of enzyme would impair ammonia handling efficiency. Thus, impaired mitochondrial ornithine transport seemed to cause hyperammonemia in the state of partial quantitative deficiency of OCT in this case.

UI	MeSH Term	Description	Entries
D008099	Liver	A large lobed glandular organ in the abdomen of vertebrates that is responsible for detoxification, metabolism, synthesis and storage of various substances.	Livers
D008297	Male		Males
D008930	Mitochondria, Liver	Mitochondria in hepatocytes. As in all mitochondria, there are an outer membrane and an inner membrane, together creating two separate mitochondrial compartments: the internal matrix space and a much narrower intermembrane space. In the liver mitochondrion, an estimated 67% of the total mitochondrial proteins is located in the matrix. (From Alberts et al., Molecular Biology of the Cell, 2d ed, p343-4)	Liver Mitochondria,Liver Mitochondrion,Mitochondrion, Liver
D009952	Ornithine	An amino acid produced in the urea cycle by the splitting off of urea from arginine.	2,5-Diaminopentanoic Acid,Ornithine Dihydrochloride, (L)-Isomer,Ornithine Hydrochloride, (D)-Isomer,Ornithine Hydrochloride, (DL)-Isomer,Ornithine Hydrochloride, (L)-Isomer,Ornithine Monoacetate, (L)-Isomer,Ornithine Monohydrobromide, (L)-Isomer,Ornithine Monohydrochloride, (D)-Isomer,Ornithine Monohydrochloride, (DL)-Isomer,Ornithine Phosphate (1:1), (L)-Isomer,Ornithine Sulfate (1:1), (L)-Isomer,Ornithine, (D)-Isomer,Ornithine, (DL)-Isomer,Ornithine, (L)-Isomer,2,5 Diaminopentanoic Acid
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D000293	Adolescent	A person 13 to 18 years of age.	Adolescence,Youth,Adolescents,Adolescents, Female,Adolescents, Male,Teenagers,Teens,Adolescent, Female,Adolescent, Male,Female Adolescent,Female Adolescents,Male Adolescent,Male Adolescents,Teen,Teenager,Youths
D000592	Amino Acid Metabolism, Inborn Errors	Disorders affecting amino acid metabolism. The majority of these disorders are inherited and present in the neonatal period with metabolic disturbances (e.g., ACIDOSIS) and neurologic manifestations. They are present at birth, although they may not become symptomatic until later in life.	Amino Acidopathies, Congenital,Amino Acid Metabolism Disorders, Inborn,Amino Acid Metabolism, Inborn Error,Amino Acid Metabolism, Inherited Disorders,Amino Acidopathies, Inborn,Congenital Amino Acidopathies,Inborn Errors, Amino Acid Metabolism,Inherited Errors of Amino Acid Metabolism,Amino Acidopathy, Congenital,Amino Acidopathy, Inborn,Congenital Amino Acidopathy,Inborn Amino Acidopathies,Inborn Amino Acidopathy
D000641	Ammonia	A colorless alkaline gas. It is formed in the body during decomposition of organic materials during a large number of metabolically important reactions. Note that the aqueous form of ammonia is referred to as AMMONIUM HYDROXIDE.
D020163	Ornithine Carbamoyltransferase Deficiency Disease	An inherited urea cycle disorder associated with deficiency of the enzyme ORNITHINE CARBAMOYLTRANSFERASE, transmitted as an X-linked trait and featuring elevations of amino acids and ammonia in the serum. Clinical features, which are more prominent in males, include seizures, behavioral alterations, episodic vomiting, lethargy, and coma. (Menkes, Textbook of Child Neurology, 5th ed, pp49-50)	OTC Deficiency,Ornithine Transcarbamylase Deficiency,Ornithine Transcarbamylase Deficiency Disease,Deficiency Disease, Ornithine Carbamoyltransferase,Deficiency Disease, Ornithine Transcarbamylase,Ornithine Carbamoyltransferase Deficiency,Ornithine Transcarbamylase Deficiency, Hyperammonemia Due To,Deficiencies, OTC,Deficiencies, Ornithine Transcarbamylase,Deficiency, OTC,Deficiency, Ornithine Transcarbamylase,OTC Deficiencies,Ornithine Transcarbamylase Deficiencies