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MLYCD gene
Reviewed by Medicinsk Expert•Last updated: 2026-10-22•Gene

MLYCD gene

The MLYCD gene provides instructions for making an enzyme that regulates the formation and breakdown of fatty acids, which are essential for energy production and cellular health.

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. 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.

This enzyme 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. The enzyme functions in several parts of the cell, including mitochondria (energy-producing centers), peroxisomes (sacs that process fatty acids), and the cytoplasm (the fluid surrounding cell structures).

Health Conditions Related to Genetic Changes

Malonyl-CoA decarboxylase deficiency

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

A lack of malonyl-CoA decarboxylase disrupts the normal balance of fatty acid formation and breakdown. This leads to characteristic features of the disorder, including:

  • Low blood glucose (hypoglycemia)
  • A heart condition called cardiomyopathy
  • A buildup of byproducts of fatty acid processing in tissues

Other Names for This Gene

  • DCMC_HUMAN
  • hMCD
  • malonyl coenzyme A decarboxylase
  • MCD

Frequently Asked Questions

Diagnosis relies on a combination of biochemical testing (elevated plasma and urine malonyl‑carnitine, high malonic acid levels), enzyme activity assays in cultured fibroblasts or lymphocytes, and confirmation by molecular genetic testing of the MLYCD gene to identify pathogenic variants.
Common early manifestations include poor feeding, failure to thrive, muscle weakness, and episodes of low blood sugar. Some children also develop cardiomyopathy (enlarged heart) or seizures within the first year of life. Early recognition is critical for prompt metabolic management.
low‑fat, high‑carbohydrate diet reduces the load of fatty acids that need to be oxidized. Medium‑chain triglyceride (MCT) oil is often avoided because it bypasses the carnitine transport step. Some clinicians also prescribe a carnitine supplement to support residual fatty‑acid oxidation, but dosing must be individualized.
MLYCD deficiency is inherited in an autosomal‑recessive pattern. Both parents of an affected child are typically carriers. Carrier testing using targeted mutation analysis or full‑gene sequencing is available for siblings, future pregnancies, and extended family members. Genetic counseling is recommended to discuss reproductive options such as prenatal diagnosis or pre‑implantation genetic testing.===
Source: MedlinePlus, National Library of Medicine

MedlinePlus brings together authoritative health information from the National Library of Medicine (NLM), the National Institutes of Health (NIH), and other government agencies and health-related organizations.

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