Biomaterial Database

The clinical evaluation of cobalamin deficiency by determination of methylmalonic acid in serum or urine is not invalidated by the presence of heterozygous methylmalonic-acidaemia. 1990

K Rasmussen, and E Nathan

Klinisk-kemisk afdeling, Aarhus Kommunehospital, Danmark.

It is well established that accumulation of methylmalonic acid may provide an early clue to the existence of tissue cobalamin (vitamin B12) deficiency. To verify whether methylmalonic acid accumulates in adult heterozygotes for inherited methylmalonic-acidaemia and thereby gives "false" positive test results for cobalamin deficiency, we measured the concentration of methylmalonic acid in serum and its urinary excretion in six patients of three children with severe methylmalonic-acidaemia. We found levels of methylmalonic acid similar to those in normal subjects. In serum, the concentrations of methylmalonic acid ranged from 0.12 to 0.39 mumol/l (reference range: 0.05-0.44 mumol/l). In urine, the values ranged from 1.18 to 2.48 mmol per mol of creatinine (reference range: 0.58-3.56). We conclude that the 2% of carriers of inherited methylmalonic-acidaemia in the general population do not invalidate the usefulness of measurement of methylmalonic acid in serum or urine for the clinical evaluation of cobalamin deficiency.

UI	MeSH Term	Description	Entries
D008297	Male		Males
D008661	Metabolism, Inborn Errors	Errors in metabolic processes resulting from inborn genetic mutations that are inherited or acquired in utero.	Inborn Errors of Metabolism,Metabolism Errors, Inborn,Error, Inborn Metabolism,Errors Metabolism, Inborn,Errors Metabolisms, Inborn,Errors, Inborn Metabolism,Inborn Errors Metabolism,Inborn Errors Metabolisms,Inborn Metabolism Error,Inborn Metabolism Errors,Metabolism Error, Inborn,Metabolism Inborn Error,Metabolism Inborn Errors,Metabolisms, Inborn Errors
D008764	Methylmalonic Acid	A malonic acid derivative which is a vital intermediate in the metabolism of fat and protein. Abnormalities in methylmalonic acid metabolism lead to methylmalonic aciduria. This metabolic disease is attributed to a block in the enzymatic conversion of methylmalonyl CoA to succinyl CoA.	Acid, Methylmalonic
D008875	Middle Aged	An adult aged 45 - 64 years.	Middle Age
D005260	Female		Females
D006579	Heterozygote	An individual having different alleles at one or more loci regarding a specific character.	Carriers, Genetic,Genetic Carriers,Carrier, Genetic,Genetic Carrier,Heterozygotes
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D000328	Adult	A person having attained full growth or maturity. Adults are of 19 through 44 years of age. For a person between 19 and 24 years of age, YOUNG ADULT is available.	Adults
D014806	Vitamin B 12 Deficiency	A nutritional condition produced by a deficiency of VITAMIN B 12 in the diet, characterized by megaloblastic anemia. Since vitamin B 12 is not present in plants, humans have obtained their supply from animal products, from multivitamin supplements in the form of pills, and as additives to food preparations. A wide variety of neuropsychiatric abnormalities is also seen in vitamin B 12 deficiency and appears to be due to an undefined defect involving myelin synthesis. (From Cecil Textbook of Medicine, 19th ed, p848)	Deficiency, Vitamin B 12,Deficiency, Vitamin B12,Vitamin B12 Deficiency,Deficiencies, Vitamin B12,Vitamin B12 Deficiencies