Biomaterial Database

Methylmalonic acidaemia due to mutase apoenzyme defect: responsive to vitamin B12 in intact fibroblasts but not in vivo. 1982

R Baumgartner, and O Giardini, and A Cantani, and G Sabetta, and M Castro

Congenital methylmalonic acidaemia (MMA-aemia) was diagnosed in an 8-month-old girl who presented with severe metabolic acidosis, hypoglycaemia and hyperglycinaemia. Vomiting, failure to thrive and apathy first appeared when breast feeding was replaced by a cows' milk formula at the age of 3 months. The patient, unresponsive to OH-Cbl therapy, was successfully treated with dietary protein restriction and with Shohl's solution. Aged 4 years 9 months, she is in good health. Studies in cultured fibroblasts revealed a defect of the MMA-CoA mutase apoenzyme. Mutase activity in cell extracts was barely detectable both with and without added coenzyme (Ado-Cbl). Addition of OH-Cbl to the culture medium improved overall propionate metabolism in intact fibroblasts but had no effect on mutase activity in cell extracts. These observations point to the presence of a very labile mutant enzyme, suggesting that the patient reported here may be suffering from yet another variant of MMA-aemia.

UI	MeSH Term	Description	Entries
D008314	Malonates	Derivatives of malonic acid (the structural formula CH2(COOH)2), including its salts and esters.
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
D008765	Methylmalonyl-CoA Mutase	An enzyme that catalyzes the conversion of methylmalonyl-CoA to succinyl-CoA by transfer of the carbonyl group. It requires a cobamide coenzyme. A block in this enzymatic conversion leads to the metabolic disease, methylmalonic aciduria. EC 5.4.99.2.	Methylmalonyl-CoA Isomerase,Isomerase, Methylmalonyl-CoA,Methylmalonyl CoA Isomerase,Methylmalonyl CoA Mutase,Mutase, Methylmalonyl-CoA
D002675	Child, Preschool	A child between the ages of 2 and 5.	Children, Preschool,Preschool Child,Preschool Children
D005260	Female		Females
D005347	Fibroblasts	Connective tissue cells which secrete an extracellular matrix rich in collagen and other macromolecules.	Fibroblast
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
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
D001051	Apoenzymes	The protein components of enzyme complexes (HOLOENZYMES). An apoenzyme is the holoenzyme minus any cofactors (ENZYME COFACTORS) or prosthetic groups required for the enzymatic function.	Apoenzyme
D014805	Vitamin B 12	A cobalt-containing coordination compound produced by intestinal micro-organisms and found also in soil and water. Higher plants do not concentrate vitamin B 12 from the soil and so are a poor source of the substance as compared with animal tissues. INTRINSIC FACTOR is important for the assimilation of vitamin B 12.	Cobalamin,Cyanocobalamin,Cobalamins,Eritron,Vitamin B12,B 12, Vitamin,B12, Vitamin