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Disease Profile

Isobutyryl-CoA dehydrogenase deficiency

Prevalence estimates on Rare Medical Network websites are calculated based on data available from numerous sources, including US and European government statistics, the NIH, Orphanet, and published epidemiologic studies. Rare disease population data is recognized to be highly variable, and based on a wide variety of source data and methodologies, so the prevalence data on this site should be assumed to be estimated and cannot be considered to be absolutely correct.


US Estimated

Europe Estimated

Age of onset






Autosomal dominant A pathogenic variant in only one gene copy in each cell is sufficient to cause an autosomal dominant disease.


Autosomal recessive Pathogenic variants in both copies of each gene of the chromosome are needed to cause an autosomal recessive disease and observe the mutant phenotype.


dominant X-linked dominant inheritance, sometimes referred to as X-linked dominance, is a mode of genetic inheritance by which a dominant gene is carried on the X chromosome.


recessive Pathogenic variants in both copies of a gene on the X chromosome cause an X-linked recessive disorder.


Mitochondrial or multigenic Mitochondrial genetic disorders can be caused by changes (mutations) in either the mitochondrial DNA or nuclear DNA that lead to dysfunction of the mitochondria and inadequate production of energy.


Multigenic or multifactor Inheritance involving many factors, of which at least one is genetic but none is of overwhelming importance, as in the causation of a disease by multiple genetic and environmental factors.


Not applicable


Other names (AKA)

IBD deficiency; ACAD8 deficiency; Acyl-CoaA dehydrogenase family, member 8, deficiency of


Congenital and Genetic Diseases; Heart Diseases; Metabolic disorders;


Isobutyryl-CoA dehydrogenase deficiency (IBD deficiency) is an inborn error of valine (an amino acid) metabolism.[1] The symptoms, which may not develop until later in infancy or childhood, can include failure to thrive, dilated cardiomyopathy, seizures, and anemia.[2][3] IBD deficiency is caused by mutations in the ACAD8 gene.[1][2] It is inherited in an autosomal recessive manner.[2][3] Treatment may include the use of L-carnitine (a safe and natural substance that helps the body's cells make energy), frequent meals, and a low-valine diet.[3]


Infants with IBD deficiency usually appear healthy at birth. Some children identified with the condition through newborn screening never develop symptoms. When symptoms do occur, they tend to vary, but may include poor feeding and growth (failure to thrive), a weakened and enlarged heart (dilated cardiomyopathy), seizures, and low numbers of red blood cells (anemia). Another feature of this disorder may be very low blood levels of carnitine (a natural substance that helps convert certain foods into energy). IBD deficiency may be worsened by long periods without food (fasting) or infections that increase the body's demand for energy.[2][3]

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.

Medical Terms Other Names
Learn More:
30%-79% of people have these symptoms
Decreased plasma carnitine
Dicarboxylic aciduria
Elevated plasma acylcarnitine levels
5%-29% of people have these symptoms
Delayed speech and language development
Deficiency of speech development
Delayed language development
Delayed speech
Delayed speech acquisition
Delayed speech development
Impaired speech and language development
Impaired speech development
Language delay
Language delayed
Language development deficit
Late-onset speech development
Poor language development
Speech and language delay
Speech and language difficulties
Speech delay

[ more ]

Dilated cardiomyopathy
Stretched and thinned heart muscle
Ketotic hypoglycemia
Mild global developmental delay
Muscular hypotonia
Low or weak muscle tone
Pulmonic stenosis
Narrowing of pulmonic valve
Throwing up
Percent of people who have these symptoms is not available through HPO
Low number of red blood cells or hemoglobin
Autosomal recessive inheritance


IBD deficiency is caused by mutations in the ACAD8 gene.[1][2] The ACAD8 gene provides instructions for making an enzyme that plays an essential role in breaking down proteins from the diet. Specifically, the enzyme is responsible for processing valine, an amino acid that is part of many proteins. If a mutation in the ACAD8 gene reduces or eliminates the activity of this enzyme, the body is unable to break down valine properly. As a result, poor growth and reduced energy production may occur.[2]


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.
  • The Newborn Screening Coding and Terminology Guide has information on the standard codes used for newborn screening tests. Using these standards helps compare data across different laboratories. This resource was created by the National Library of Medicine.
  • 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.


    There is no standard treatment protocol for IBD deficiency. Infants diagnosed through newborn screening are encouraged to work with a metabolic disease specialist and a dietician experienced in metabolic disorders. Some treatments may be recommended even if no symptoms have been observed. Treatment may be needed throughout life. The following treatments may be recommended for some babies and children with IBD deficiency.[3] 

    • Children with IBD deficiency may be helped by taking L-carnitine, a safe and natural substance which helps the body's cells make energy and get rid of harmful wastes. L-carnitine may also help to prevent or treat the heart problems and anemia seen in children with IBD deficiency.
    • Some infants and children with IBD deficiency may be advised to avoid fasting. Going without food for a long time causes the body to use its stores of fat and protein for energy. In some people with IBD deficiency, this may lead to the build up of harmful substances in the blood. Eating frequently (every 4 to 6 hours) may help to avoid these health effects.
    • While most children with IBD deficiency do fine without a change in diet, a low-valine food plan might be necessary. Valine is found in all foods with protein. Foods high in valine, such as dairy products, meat, poultry, fish, eggs, dried beans and legumes, nuts and peanut butter should be limited. There are medical foods such low-protein flours, pastas, rice, and special formulas that are made especially for people with organic acid disorders. Your dietician / physician can advise you on whether you should use these foods to supplement your child’s diet.


    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

      Learn more

      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 Isobutyryl-CoA dehydrogenase deficiency. This website is maintained by the National Library of Medicine.
      • The Screening, Technology And Research in Genetics (STAR-G) Project has a fact sheet on this condition, which was written specifically for families that have received a diagnosis as a result of newborn screening. This fact sheet provides general information about the condition and answers questions that are of particular concern to parents.

        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 Isobutyryl-CoA dehydrogenase deficiency. Click on the link to view a sample search on this topic.


          1. Isobutyryl-CoA dehydrogenase deficiency. Orphanet. 2007; https://www.orpha.net/consor/cgi-bin/OC_Exp.php?Lng=EN&Expert=79159.
          2. Isobutyryl-CoA dehydrogenase deficiency. Genetics Home Reference (GHR). June 2010; https://ghr.nlm.nih.gov/condition/isobutyryl-coa-dehydrogenase-deficiency.
          3. Organic Acid Oxidation Disorders : Isobutyryl-CoA dehydrogenase deficiency. Screening, Technology and Research in Genetics (STAR-G). April 20, 2016; https://www.newbornscreening.info/Parents/organicaciddisorders/ICoA.html.

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