MMA Methylmalonic Acidemia

Methylmalonic Acidemia by.Aadil Syed

Methylmalonic acidemia is also called MMA, and it is an autosomal recessive metabolic disorder.It is a classical type of acidemia.

Methaylmalonic acidemia stems from several genotypes and secondary hyperammonemia. The disorder can result in death if undiagnosed or left untreated.

Ginetic

The inherited forms of methylmalonic acidemia cause defects in the metabolic pathway where methylmalonyl-coenzyme A (CoA) is converted into succinyl-CoA by the enzyme methylmalonyl-CoA mutase.

Vitamin B is also needed for the conversion of methylmalonyl-CoA to Succinyl-CoA. Mutations leading to defects in vitamin B₁₂ metabolism or in its transport frequently result in the development of methylmalonic acidemia.

This disorder has an autosomal recessive inheritance pattern and this means that the defective gene is located on an autosome, and two copies of the gene—one from each parent and this must be inherited to be affected by the disorder. The parents of a child with an autosomal recessive disorder are carriers ( a carrier is a person who has a g of one copy of the defeene but it is not dominant so they don’t hagenee it but their offspring may have it) , but are usually not affected by the disorder.

Nutrition

A severe nutritional deficiency of vitamin B₁₂ can also result in methylmalonic acidemia.^[6] Methylmalonyl CoA requires vitamin B₁₂ to form succinyl-CoA. When the amount of B₁₂ is insufficient for the conversion of cofactor methylmalonyl-CoA into succinyl-CoA, the buildup of unused methylmalonyl-CoA eventually leads to methylmalonic acidemia. This diagnosis is often used as an indicator of vitamin B₁₂deficiency in serum.^[7]

Pathogenesis

Methylmalonic acidemia has varying diagnoses, treatment requirements and prognoses, which are determined by the specific genetic mutation causing the inherited form of the disorder.^[4] The following are the known genotypes responsible for methylmalonic acidemia