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

2-methylbutyryl-CoA dehydrogenase deficiency


Other Names:
SBCAD deficiency; 2-methylbutyric aciduria; Short branched-chain acyl-CoA dehydrogenase deficiency
Categories:
2-methylbutyryl-CoA dehydrogenase deficiency is an organic acid disorder in which individuals lack adequate levels of an enzyme called 2-methylbutyryl-CoA dehydrogenase. This enzyme assists in the processing of a particular amino acid called isoleucine. The inability to process isoleucine correctly leads to the buildup of the amino acid in the body.  The buildup can cause a variety of health problems, which vary widely from severe and life-threatening to mild or absent.  Signs and symptoms of the disorder can begin a few days after birth or later in childhood. The initial symptoms often include poor feeding, lack of energy, vomiting, and irritability. These symptoms sometimes progress to serious medical problems such as difficulty breathing, seizures, and coma.[1][[2] This condition is caused by mutations in the ACADSB gene. It is inherited in an autosomal recessive pattern.[1] Treatment, when needed, includes a low-protein diet, specialty formulas, foods and supplements, and careful observation if illness occurs.[2] 
Last updated: 4/22/2016

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.

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Medical Terms Other Names
Learn More:
HPO ID
Percent of people who have these symptoms is not available through HPO
Apneic episodes in infancy 0005949
Autosomal recessive inheritance 0000007
Exotropia
Outward facing eye ball
0000577
Generalized amyotrophy
Diffuse skeletal muscle wasting
Generalized muscle degeneration
Muscle atrophy, generalized
[ more ] 		0003700
Generalized hypotonia
Decreased muscle tone
Low muscle tone
[ more ] 		0001290
Global developmental delay 0001263
Hypoglycemia
Low blood sugar
0001943
Hypothermia
Abnormally low body temperature
0002045
Infantile onset
Onset in first year of life
Onset in infancy
[ more ] 		0003593
Lethargy 0001254
Microcephaly
Abnormally small skull
Decreased circumference of cranium
Decreased size of skull
Reduced head circumference
Small head circumference
[ more ] 		0000252
Motor delay 0001270
Muscular hypotonia
Low or weak muscle tone
0001252
Seizure 0001250
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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

The resources below provide information about treatment options for this condition. If you have questions about which treatment is right for you, talk to your healthcare professional.

Management Guidelines

  • GeneReviews provides current, expert-authored, peer-reviewed, full-text articles describing the application of genetic testing to the diagnosis, management, and genetic counseling of patients with specific inherited conditions. Click on the link to view the article on organic acidemias.

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

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

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.

News

Other Conferences

  • The International Network for Fatty Acid Oxidation Research and Management (INFORM) was formed in order to promote research and discussion into the cause, diagnosis, and management of fatty acid oxidation disorders (FAODs). They offer several learning opportunities throughout the year for patients, families, and researchers. INFORM's Annual Meeting will be held on August 30th and 31st, 2020 in Freiberg, Germany preceding the Society for the Study of Inborn Errors of Metabolism (SSIEM). The Network also continues to provide a collaborative framework for ongoing communication and research regarding FAODs.

Questions sent to GARD may be posted here if the information could be helpful to others. We remove all identifying information when posting a question to protect your privacy. If you do not want your question posted, please let us know. Submit a new question

  • I have a student who has 2-methylbutyryl-coa dehydrogenase, what should her diet be? What types of food should she be eating, what foods should she avoid? See answer


  1. 2-methylbutyryl-coenzyme A dehydrogenase deficiency. Genetics Home Reference. April 2007; https://ghr.nlm.nih.gov/condition/2-methylbutyryl-coa-dehydrogenase-deficiency.
  2. 2-methylbutyryl CoA dehydrogenase deficiency. Screening, Technology and Research in Genetics (STAR-G). August 29, 2013; http://www.newbornscreening.info/Parents/organicaciddisorders/2MBC.html.