methylmalonic acid

Methylmalonic acid is used as a more specific test of B deficiency.

Increased methylmalonic acid levels may indicate a vitamin B deficiency.

Direct measurement of blood cobalamin remains the gold standard because the test for elevated methylmalonic acid is not specific enough.

The level of methylmalonic acid is not elevated in folic acid deficiency.

Methylmalonic acid, if not properly handled by B, remains in the myelin sheath, causing fragility.

Methylmalonyl-CoA is the thioester consisting of coenzyme A linked to methylmalonic acid.

One way to differentiate between folate deficiency from vitamin B deficiency is by testing for methylmalonic acid levels.

Without B levels of methylmalonic acid (MMA) and homocysteine increase because the reactions cannot proceed.

Serum homocysteine and methylmalonic acid levels are considered more reliable indicators of B deficiency than the concentration of B in blood.

These symptoms are consistent with B12 deficiency in absence of anemia, which should always be ruled out directly by checking B12, homocysteine and methylmalonic acid.

This functionality is lost in vitamin B deficiency, and can be measured clinically as an increased methylmalonic acid (MMA) level.

Methylmalonic acid (MMA) is a dicarboxylic acid that is a C-methylated derivative of malonate.

Approximately 10% of patients with vitamin B levels between 200-400pg/l will have a vitamin B deficiency on the basis of elevated levels of homocysteine and methylmalonic acid.

Additionally, organic acid analysis and/or quantitative determination of methylmalonic acid should help to exclude cobalamin (vitamin B12) defects and vitamin B12 deficiency giving a differential diagnosis.

The coenzyme A linked form of methylmalonic acid, methylmalonyl-CoA, is converted into succinyl-CoA by methylmalonyl-CoA mutase, in a reaction that requires vitamin B as a cofactor.

In addition to checking serum B, checking the levels of other compounds (particularly methylmalonic acid) may be necessary to accurately detect a deficiency state, because serum levels do not necessarily correlate with efficient utilization of B.

Routine monitoring of methylmalonic acid levels in urine is an option for people who may not be getting enough dietary B, as a rise in methylmalonic acid levels may be an early indication of deficiency.