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URL of this page: https://medlineplus.gov/genetics/gene/mlycd/

MLYCD gene

malonyl-CoA decarboxylase

Normal Function

The MLYCD gene provides instructions for making an enzyme called malonyl-CoA decarboxylase. This enzyme helps regulate the formation and breakdown of a group of fats called fatty acids. Fatty acids provide energy, build cell membranes, produce hormones, and carry out many other important processes in the body. 

Malonyl-CoA decarboxylase helps regulate the levels of fatty acids in the body. To do this, malonyl-CoA decarboxylase facilitates the chemical reaction that converts a molecule called malonyl-CoA into a molecule called acetyl-CoA. Acetyl-CoA is needed to form new fatty acids (fatty acid biosynthesis).  

Malonyl-CoA stops enzymes from breaking down fatty acids (fatty acid oxidation). When cells need new fatty acids, malonyl-CoA decarboxylase helps convert malonyl-CoA into acetyl-CoA. Through its regulation of malonyl-CoA, malonyl-CoA decarboxylase helps control when fatty acids are formed and when they are broken down. 

Malonyl-CoA decarboxylase is primarily found in the heart (cardiac) muscles, but it is also found in the brain, muscles used for movement (skeletal muscles), small intestine, liver, pancreas, and kidneys.  

Health Conditions Related to Genetic Changes

Malonyl-CoA decarboxylase deficiency

Genetic changes that cause disease are called pathogenic variants. Pathogenic variants in the MLYCD gene cause malonyl-CoA decarboxylase deficiency. This condition prevents the body from converting fatty acids into energy. Signs and symptoms of malonyl-CoA decarboxylase deficiency begin in infancy or childhood. These include delayed development, low blood glucose (hypoglycemia), and a weakened and enlarged cardiac muscle (cardiomyopathy). 

Pathogenic variants in the MLYCD gene prevent malonyl-CoA decarboxylase from functioning properly. A shortage of functional malonyl-CoA decarboxylase disrupts the normal balance of fatty acid formation and breakdown in the body. Without enough functional enzyme, malonyl-CoA cannot be converted to acetyl-CoA, which leads to a buildup of malonyl-CoA. Too much malonyl-CoA can impair the activity of other enzymes that break down fatty acids to create energy. This reduced supply of energy seems to have a particular impact on the brain and heart, although it is unclear how the specific features of this condition, such as cardiomyopathy and developmental delays, occur.  

More About This Health Condition

Other Names for This Gene

  • hMCD
  • MCD

Additional Information & Resources

Tests Listed in the Genetic Testing Registry

Scientific Articles on PubMed

Catalog of Genes and Diseases from OMIM

Gene and Variant Databases

References

  • Chapel-Crespo C, Gavrilov D, Sowa M, Myers J, Day-Salvatore DL, Lynn H, Regier D, Starin D, Steenari M, Schoonderwoerd K, Abdenur JE. Clinical, biochemical and molecular characteristics of malonyl-CoA decarboxylase deficiency and long-term follow-up of nine patients. Mol Genet Metab. 2019 Sep-Oct;128(1-2):113-121. doi: 10.1016/j.ymgme.2019.07.015. Epub 2019 Jul 29. No abstract available. Citation on PubMed
  • Kasapkara CS, Civelek Urey B, Ceylan AC, Unal Uzun O, Cetin II. Malonyl coenzyme A decarboxylase deficiency with a novel mutation. Cardiol Young. 2021 Sep;31(9):1535-1537. doi: 10.1017/S104795112100113X. Epub 2021 Mar 22. Citation on PubMed
  • Salomons GS, Jakobs C, Pope LL, Errami A, Potter M, Nowaczyk M, Olpin S, Manning N, Raiman JA, Slade T, Champion MP, Peck D, Gavrilov D, Hillman R, Hoganson GE, Donaldson K, Shield JP, Ketteridge D, Wasserstein M, Gibson KM. Clinical, enzymatic and molecular characterization of nine new patients with malonyl-coenzyme A decarboxylase deficiency. J Inherit Metab Dis. 2007 Feb;30(1):23-8. doi: 10.1007/s10545-006-0514-6. Epub 2006 Dec 20. Citation on PubMed
  • Surendran S, Sacksteder KA, Gould SJ, Coldwell JG, Rady PL, Tyring SK, Matalon R. Malonyl CoA decarboxylase deficiency: C to T transition in intron 2 of the MCD gene. J Neurosci Res. 2001 Sep 15;65(6):591-4. doi: 10.1002/jnr.1189. Citation on PubMed
  • Wightman PJ, Santer R, Ribes A, Dougherty F, McGill N, Thorburn DR, FitzPatrick DR. MLYCD mutation analysis: evidence for protein mistargeting as a cause of MLYCD deficiency. Hum Mutat. 2003 Oct;22(4):288-300. doi: 10.1002/humu.10264. Citation on PubMed
  • Zhang JM, Hao LL, Qiu WJ, Zhang HW, Chen T, Ji WJ, Zhang Y, Liu F, Gu XF, Yang SH, Han LS. Clinical, biochemical and genetic characteristics and long-term follow-up of five patients with malonyl-CoA decarboxylase deficiency. Brain Dev. 2024 Oct;46(9):286-293. doi: 10.1016/j.braindev.2024.07.001. Epub 2024 Jul 27. Citation on PubMed

The information on this site should not be used as a substitute for professional medical care or advice. Contact a health care provider if you have questions about your health.