metyylmalonihappo

Metyylimalonihappo, also known as methylmalonic acid (MMA), is a dicarboxylic acid with the chemical formula C4H6O4. It is an intermediate in the metabolism of fatty acids and amino acids. Specifically, it is a product of the breakdown of valine, isoleucine, methionine, and threonine. In a healthy individual, MMA is converted to succinyl-CoA by the enzyme methylmalonyl-CoA mutase, which requires vitamin B12 as a cofactor.

Elevated levels of methylmalonic acid in the blood or urine can be indicative of several medical conditions. The most common cause of MMA accumulation is vitamin B12 deficiency. Without sufficient vitamin B12, the methylmalonyl-CoA mutase enzyme cannot function properly, leading to a buildup of MMA. This can occur due to inadequate dietary intake of vitamin B12, malabsorption issues (such as pernicious anemia or gastrointestinal disorders), or certain medications.

Methylmalonic acidemia is a rare inherited metabolic disorder where individuals have a deficiency in the methylmalonyl-CoA mutase enzyme or its cofactor, adenosylcobalamin. This genetic condition leads to severe accumulation of MMA and other related metabolites, causing serious health problems if untreated, including developmental delays, neurological issues, and metabolic crises.

Measuring methylmalonic acid levels is a common diagnostic tool for vitamin B12 deficiency, often considered more sensitive than measuring vitamin B12 itself, especially in early stages or in cases where folate levels are also abnormal. Elevated MMA can also be seen in individuals with chronic kidney disease, as the kidneys play a role in excreting MMA.