National Center for Advancing and Translational Sciences Genetic and Rare Diseases Information Center, a program of the National Center for Advancing and Translational Sciences

Malonyl-CoA decarboxylase deficiency


Other Names:
Malonic aciduria; Malonicaciduria; Malonic acidemia; Malonic aciduria; Malonicaciduria; Malonic acidemia; MCD deficiency See More
Categories:
The following summary is from Orphanet, a European reference portal for information on rare diseases and orphan drugs.
orphanet

Orpha Number: 943

Definition
Malonic aciduria is a metabolic disorder caused by deficiency of malonyl-CoA decarboxylase (MCD).

Epidemiology
It is a very rare disorder that has been described in less than 20 patients.

Clinical description
This condition usually presents in early childhood and the manifestations are variable. The majority of patients are developmentally delayed with other features that include hypotonia, seizures, hypoglycaemia, metabolic acidosis, cardiomyopathy and diarrhoea.

Etiology
The disease is caused by mutations in the malonyl-CoA decarboxylase gene (MLYCD, chromosome 16q24) and is inherited as an autosomal recessive trait. The MCD enzyme is involved in the degradation of malonyl-CoA and it appears that inhibition of fatty acid synthesis as a result of malonyl-CoA accumulation is responsible for at least some of the clinical manifestations of the disorder.

Diagnostic methods
The diagnosis of malonic aciduria can be made by detecting elevated levels of organic acids (in particular malonic and methylmalonic acid) in the urine and high levels of malonylcarnitine in the blood. The diagnosis is confirmed by demonstrating reduced enzyme activity in cultured skin fibroblasts. Identification of the MLYCD gene mutation may also be useful for diagnosis and for genetic counselling.

Antenatal diagnosis
Screening of newborns may be possible through detection of elevated blood levels of malonylcarnitine using electrospray ionisation tandem mass spectrometry (ESI-MS/MS). Prenatal screening is theoretically possible through enzyme or DNA analysis of amniocytes or chorionic villus samples.

Management and treatment
The principle treatment is dietary, with patients being recommended to follow a low fat/high carbohydrate diet. Carnitine supplements may also be recommended.

Prognosis
The prognosis for patients is variable but the disease can be lethal in the neonatal period.

Visit the Orphanet disease page for more resources.
Last updated: 12/1/2006

This table lists symptoms that people with this disease may have. For most diseases, symptoms will vary from person to person. People with the same disease may not have all the symptoms listed. This information comes from a database called the Human Phenotype Ontology (HPO) . The HPO collects information on symptoms that have been described in medical resources. The HPO is updated regularly. Use the HPO ID to access more in-depth information about a symptom.

Showing of 17 |
Medical Terms Other Names
Learn More:
HPO ID
5%-29% of people have these symptoms
Pachygyria
Fewer and broader ridges in brain
0001302
Percent of people who have these symptoms is not available through HPO
Abdominal pain
Pain in stomach
Stomach pain
[ more ] 		0002027
Autosomal recessive inheritance 0000007
Chronic constipation
Infrequent bowel movements
0012450
Constipation 0002019
Diarrhea
Watery stool
0002014
Generalized hypotonia
Decreased muscle tone
Low muscle tone
[ more ] 		0001290
Global developmental delay 0001263
Hypertrophic cardiomyopathy
Enlarged and thickened heart muscle
0001639
Hypoglycemia
Low blood sugar
0001943
Ketosis
High levels of ketone bodies
0001946
Lactic acidosis
Increased lactate in body
0003128
Metabolic acidosis 0001942
Muscular hypotonia
Low or weak muscle tone
0001252
Seizure 0001250
Short stature
Decreased body height
Small stature
[ more ] 		0004322
Vomiting
Throwing up
0002013
Showing of 17 |
Last updated: 7/1/2020

Making a diagnosis for a genetic or rare disease can often be challenging. Healthcare professionals typically look at a person’s medical history, symptoms, physical exam, and laboratory test results in order to make a diagnosis. The following resources provide information relating to diagnosis and testing for this condition. If you have questions about getting a diagnosis, you should contact a healthcare professional.

Newborn Screening

  • An ACTion (ACT) sheet is available for this condition that describes the short-term actions a health professional should follow when an infant has a positive newborn screening result. ACT sheets were developed by experts in collaboration with the American College of Medical Genetics.
  • An Algorithm flowchart is available for this condition for determining the final diagnosis in an infant with a positive newborn screening result. Algorithms are developed by experts in collaboration with the American College of Medical Genetics.
  • Baby's First Test is the nation's newborn screening education center for families and providers. This site provides information and resources about screening at the local, state, and national levels and serves as the Clearinghouse for newborn screening information.
  • National Newborn Screening and Global Resource Center (NNSGRC) provides information and resources in the area of newborn screening and genetics to benefit health professionals, the public health community, consumers and government officials.

If you need medical advice, you can look for doctors or other healthcare professionals who have experience with this disease. You may find these specialists through advocacy organizations, clinical trials, or articles published in medical journals. You may also want to contact a university or tertiary medical center in your area, because these centers tend to see more complex cases and have the latest technology and treatments.

If you can’t find a specialist in your local area, try contacting national or international specialists. They may be able to refer you to someone they know through conferences or research efforts. Some specialists may be willing to consult with you or your local doctors over the phone or by email if you can't travel to them for care.

You can find more tips in our guide, How to Find a Disease Specialist. We also encourage you to explore the rest of this page to find resources that can help you find specialists.

Healthcare Resources

Research helps us better understand diseases and can lead to advances in diagnosis and treatment. This section provides resources to help you learn about medical research and ways to get involved.

Clinical Research Resources

  • ClinicalTrials.gov lists trials that are related to Malonyl-CoA decarboxylase deficiency. Click on the link to go to ClinicalTrials.gov to read descriptions of these studies.

    Please note: Studies listed on the ClinicalTrials.gov website are listed for informational purposes only; being listed does not reflect an endorsement by GARD or the NIH. We strongly recommend that you talk with a trusted healthcare provider before choosing to participate in any clinical study.

Support and advocacy groups can help you connect with other patients and families, and they can provide valuable services. Many develop patient-centered information and are the driving force behind research for better treatments and possible cures. They can direct you to research, resources, and services. Many organizations also have experts who serve as medical advisors or provide lists of doctors/clinics. Visit the group’s website or contact them to learn about the services they offer. Inclusion on this list is not an endorsement by GARD.

Organizations Supporting this Disease

These resources provide more information about this condition or associated symptoms. The in-depth resources contain medical and scientific language that may be hard to understand. You may want to review these resources with a medical professional.

Where to Start

  • Genetics Home Reference (GHR) contains information on Malonyl-CoA decarboxylase deficiency. This website is maintained by the National Library of Medicine.

In-Depth Information

  • The Monarch Initiative brings together data about this condition from humans and other species to help physicians and biomedical researchers. Monarch’s tools are designed to make it easier to compare the signs and symptoms (phenotypes) of different diseases and discover common features. This initiative is a collaboration between several academic institutions across the world and is funded by the National Institutes of Health. Visit the website to explore the biology of this condition.
  • Online Mendelian Inheritance in Man (OMIM) is a catalog of human genes and genetic disorders. Each entry has a summary of related medical articles. It is meant for health care professionals and researchers. OMIM is maintained by Johns Hopkins University School of Medicine. 
  • Orphanet is a European reference portal for information on rare diseases and orphan drugs. Access to this database is free of charge.
  • PubMed is a searchable database of medical literature and lists journal articles that discuss Malonyl-CoA decarboxylase deficiency. Click on the link to view a sample search on this topic.

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