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Methylmalonic Acid & Vitamin B12

Jun 7, 2011 | By Ruth Coleman

Vitamin B12 is absorbed in one part of the small intestines and stored in the liver. The cells of the body will use this vitamin to make DNA, break down folic acid, and make and repair myelin. Methylmalonic acid is formed if the cells do not have enough vitamin B12.

Vitamin B12

Chemically, vitamin B12 is the most complex vitamin. Also referred to as cobalamin, as complicated as its structure is, it is only made by certain microorganisms and found in animals. Thus, people who are strict vegetarians risk developing a deficiency of vitamin B12. The liver stores so much of this vitamin, however, it would take many years for this to occur, according to Gerhard Meisenberg, Ph.D., of the Department of Biochemistry at Ross University School of Medicine in "Principles of Medical Biochemistry." The vitamin is absorbed in the last part of the small intestines, so any disease that affects that area will also lower its absorption.

Vitamin B12 and Methylmalonic Acid

Vitamin B12 is needed to make DNA and to metabolize folic acid, because a form of folic acid is necessary for the red blood cells to mature. People also need vitamin B12 to make and repair myelin, which covers the nerves for fast signaling. The cells take the methionine, isoleucine and valine amino acids to make methylmalonyl-CoA. With the help of vitamin B12, they then change methylmalonyl-CoA to succinyl-CoA. If there is not enough vitamin B12, methylmalonyl-CoA is changed to methylmalonic acid, which may result in abnormal myelin, writes Charles Linker, M.D., clinical professor of medicine at the University of California in "Current Medical Diagnosis & Treatment."

Methylmalonic Acidemia

According to the National Institutes of Health, approximately one in every 25,000 to 48,000 babies is born with this hereditary disease. It develops because they do not have enough of an enzyme called methylmalonyl-CoA mutase to change methylmalonyl-CoA to succinyl-CoA or do not have enough vitamin B12. As a result, methylmalonic acid builds up in the bloodstream. The babies may have symptoms when they start eating protein, because protein is broken down to amino acids, and three amino acids are used to make methylmalonyl-CoA. They can vomit, have seizures and have an abnormal development.

Treatment for Methylmalonic Acidemia

Irini Manoli, M.D., Ph.D. of the National Institutes of Health writes in "Gene Reviews" about the treatment for methylmalonic acidemia. Parents must closely monitor the diet, so the child consumes a lot of calories but not a lot of protein. The physician may even recommend the elimination of all protein from the diet. Children with this disorder will not only need vitamin B12 supplements, they will also need carnitine supplements, because carnitine is used by the cells to change fatty acids into energy. Some children may need a kidney transplant, liver transplant or both. This will give them the cells they need to break down methylmalonic acid.

References

Article reviewed by Khalid Adad Last updated on: Jun 7, 2011

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