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Genetics Home Reference: your guide to understanding genetic conditions     A service of the U.S. National Library of Medicine®


Reviewed January 2010

What is the official name of the MLYCD gene?

The official name of this gene is “malonyl-CoA decarboxylase.”

MLYCD is the gene's official symbol. The MLYCD gene is also known by other names, listed below.

What is the normal function of the MLYCD gene?

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. Many tissues, including heart (cardiac) muscle, use fatty acids as a major source of energy. The body also uses fatty acids to build cell membranes, produce hormones, and carry out many other important processes.

Malonyl-CoA decarboxylase is responsible for the chemical reaction that converts a molecule called malonyl-CoA to a molecule called acetyl-CoA. This reaction is an important step in the breakdown of fatty acids. Acetyl-CoA is then used to make new fatty acids and can also be used to produce energy.

Malonyl-CoA decarboxylase is most active in cardiac muscle and in muscles used for movement (skeletal muscles). It is also found in other organs and tissues, including the brain, small intestine, liver, kidney, and pancreas. This enzyme probably functions in several parts of the cell, including mitochondria, which are cells' energy-producing centers, and peroxisomes, which are small sacs that process fatty acids and other molecules. Malonyl-CoA decarboxylase also functions in the fluid that surrounds these cell structures (the cytoplasm).

How are changes in the MLYCD gene related to health conditions?

malonyl-CoA decarboxylase deficiency - caused by mutations in the MLYCD gene

More than 20 mutations in the MLYCD gene have been identified in people with malonyl-CoA decarboxylase deficiency. Some of these mutations lead to the production of an abnormally short, nonfunctional version of malonyl-CoA decarboxylase or prevent the gene from producing any of this enzyme. Other mutations change the structure of the enzyme so it cannot be delivered to the parts of the cell where it is needed (such as mitochondria and peroxisomes).

A lack of malonyl-CoA decarboxylase disrupts the normal balance of fatty acid formation and breakdown in the body. As a result, fatty acids cannot be converted to energy, which leads to characteristic features of this disorder including low blood sugar (hypoglycemia) and a heart condition called cardiomyopathy. Byproducts of fatty acid processing build up in tissues, which also contributes to the signs and symptoms of malonyl-CoA decarboxylase deficiency.

Where is the MLYCD gene located?

Cytogenetic Location: 16q24

Molecular Location on chromosome 16: base pairs 83,899,125 to 83,916,182

(Homo sapiens Annotation Release 107, GRCh38.p2) (NCBI (

The MLYCD gene is located on the long (q) arm of chromosome 16 at position 24.

The MLYCD gene is located on the long (q) arm of chromosome 16 at position 24.

More precisely, the MLYCD gene is located from base pair 83,899,125 to base pair 83,916,182 on chromosome 16.

See How do geneticists indicate the location of a gene? ( in the Handbook.

Where can I find additional information about MLYCD?

You and your healthcare professional may find the following resources about MLYCD helpful.

You may also be interested in these resources, which are designed for genetics professionals and researchers.

What other names do people use for the MLYCD gene or gene products?

  • hMCD
  • malonyl coenzyme A decarboxylase
  • MCD

See How are genetic conditions and genes named? ( in the Handbook.

What glossary definitions help with understanding MLYCD?

acids ; breakdown ; cardiac ; cardiomyopathy ; cell ; CoA ; coenzyme A ; cytoplasm ; deficiency ; enzyme ; fatty acids ; gene ; hypoglycemia ; intestine ; kidney ; mitochondria ; molecule ; pancreas ; peroxisomes

You may find definitions for these and many other terms in the Genetics Home Reference Glossary.


  • FitzPatrick DR, Hill A, Tolmie JL, Thorburn DR, Christodoulou J. The molecular basis of malonyl-CoA decarboxylase deficiency. Am J Hum Genet. 1999 Aug;65(2):318-26. (
  • Gao J, Waber L, Bennett MJ, Gibson KM, Cohen JC. Cloning and mutational analysis of human malonyl-coenzyme A decarboxylase. J Lipid Res. 1999 Jan;40(1):178-82. (
  • NCBI Gene (
  • Sacksteder KA, Morrell JC, Wanders RJ, Matalon R, Gould SJ. MCD encodes peroxisomal and cytoplasmic forms of malonyl-CoA decarboxylase and is mutated in malonyl-CoA decarboxylase deficiency. J Biol Chem. 1999 Aug 27;274(35):24461-8. (
  • Saggerson D. Malonyl-CoA, a key signaling molecule in mammalian cells. Annu Rev Nutr. 2008;28:253-72. doi: 10.1146/annurev.nutr.28.061807.155434. Review. (
  • 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. Epub 2006 Dec 20. (
  • Sambandam N, Steinmetz M, Chu A, Altarejos JY, Dyck JR, Lopaschuk GD. Malonyl-CoA decarboxylase (MCD) is differentially regulated in subcellular compartments by 5'AMP-activated protein kinase (AMPK). Studies using H9c2 cells overexpressing MCD and AMPK by adenoviral gene transfer technique. Eur J Biochem. 2004 Jul;271(13):2831-40. (
  • 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. (
  • 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. (


The resources on this site should not be used as a substitute for professional medical care or advice. Users seeking information about a personal genetic disease, syndrome, or condition should consult with a qualified healthcare professional. See How can I find a genetics professional in my area? ( in the Handbook.

Reviewed: January 2010
Published: February 8, 2016