The MCEE gene provides instructions for making an enzyme called methylmalonyl CoA epimerase, which converts one form of the molecule methylmalonyl CoA to another. Specifically, the enzyme converts D-methylmalonyl CoA to L-methylmalonyl CoA. This conversion takes place within the pathway that converts the molecule propionyl-CoA to succinyl-CoA. This pathway is important in the breakdown of certain protein building blocks (amino acids), specific fats (lipids), and cholesterol.
At least three mutations in the MCEE gene have been found to cause methylmalonic acidemia, a condition characterized by feeding difficulties, developmental delay, and long-term health problems. These mutations are thought to result in the production of a methylmalonyl CoA epimerase enzyme with little or no function. People with methylmalonic acidemia caused by mutations in the MCEE gene typically have milder signs and symptoms than people with the condition caused by mutations in other genes. The features may be milder because there is an alternate pathway for the conversion of propionyl-CoA to succinyl-CoA that does not involve methylmalonyl CoA epimerase, so some succinyl-Co is produced even when there are mutations in the MCEE gene. This alternate pathway cannot compensate for the breakdown of certain molecules that occurs in the regular pathway, so people with MCEE gene mutations still have a buildup of the byproducts of some amino acids and certain fats. As a result, these toxic compounds build up in the body's organs and tissues, causing the signs and symptoms of methylmalonic acidemia.
- DL-methylmalonyl-CoA racemase
- glyoxalase domain containing 2
- methylmalonyl CoA epimerase
- methylmalonyl-CoA epimerase, mitochondrial
- methylmalonyl-CoA epimerase, mitochondrial precursor