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

Short-chain acyl-CoA dehydrogenase deficiency


Other Names:
SCAD deficiency; ACADS deficiency; SCADH deficiency; SCAD deficiency; ACADS deficiency; SCADH deficiency; Lipid-storage myopathy secondary to short-chain acyl-CoA dehydrogenase deficiency; Short-chain acyl-coenzyme A dehydrogenase deficiency See More
Categories:
Short-chain acyl-CoA dehydrogenase (SCAD) deficiency is a rare genetic condition that prevents the body from converting certain fats (called short-chain fatty acids) into energy.[1] This condition belongs to a group of disorders known as fatty acid oxidation disorders (FOD).[2] SCAD deficiency is caused by mutations in the ACADS gene.[1] These mutations lead to a shortage (deficiency) of an enzyme known as short-chain acyl-CoA dehydrogenase, which is involved in the breakdown of short-chain fatty acids. When not enough of this enzyme is present, excessive amounts of fatty acids and ammonia accumulate in the body.[1][2] The symptoms of SCAD deficiency include a lack of energy, poor growth, and developmental delay.[1] Treatment for this condition typically includes a low-fat diet and avoidance of long periods without food (fasting).[2]
Last updated: 2/5/2016
Some infants and children with SCAD deficiency may exhibit vomiting, low blood sugar (hypoglycemia), a lack of energy (lethargy), poor feeding, and failure to gain weight and grow at the expected rate (failure to thrive). Other features of this disorder may include poor muscle tone (hypotonia), seizures, developmental delay, and a small head size (microcephaly). The symptoms of SCAD deficiency may be triggered by periods of fasting or during illnesses such as viral infections. In some cases, signs and symptoms may not appear until adulthood, when some individuals may develop muscle weakness and wasting. Some people are never diagnosed because they have very mild symptoms.[1]
Last updated: 2/5/2016

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.

Showing of 20 |
Medical Terms Other Names
Learn More:
HPO ID
5%-29% of people have these symptoms
Progressive external ophthalmoplegia 0000590
Percent of people who have these symptoms is not available through HPO
Abnormality of the cerebral white matter 0002500
Autosomal recessive inheritance 0000007
Cardiomyopathy
Disease of the heart muscle
0001638
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 ] 		0000750
Episodic metabolic acidosis 0004911
Ethylmalonic aciduria 0003219
Facial palsy
Bell's palsy
0010628
Failure to thrive
Faltering weight
Weight faltering
[ more ] 		0001508
Feeding difficulties in infancy 0008872
Flexion contracture
Flexed joint that cannot be straightened
0001371
Generalized hypotonia
Decreased muscle tone
Low muscle tone
[ more ] 		0001290
Global developmental delay 0001263
Lethargy 0001254
Muscular hypotonia
Low or weak muscle tone
0001252
Myopathy
Muscle tissue disease
0003198
Neonatal onset 0003623
Psychosis 0000709
Scoliosis 0002650
Seizure 0001250
Showing of 20 |
Last updated: 7/1/2020
Mutations in the ACADS gene cause SCAD deficiency. These mutations lead to inadequate levels of an enzyme called short-chain acyl-CoA dehydrogenase. This enzyme is important for the breakdown of a particular type of fat called short-chain fatty acids. Reduced levels of this enzyme prevent short-chain fatty acids from being further broken down and processed in the mitochondria (the energy-producing centers inside cells). As a result, these short-chain fatty acids are not converted into energy, which can lead to the signs and symptoms of this disorder, such as lethargy, hypoglycemia, and muscle weakness.[1]
Last updated: 2/5/2016
Short-chain acyl-CoA dehydrogenase (SCAD) deficiency is inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations. Most often, the parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but do not show signs and symptoms of the condition. [1]
Last updated: 2/5/2016

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.
Treatment of short-chain acyl-CoA dehydrogenase (SCAD) deficiency usually consists of avoidance of fasting and a low fat diet. Supplemental carnitine may be recommended for some affected children during acute crises. Episodes of acute metabolic acidosis may be treated with intravenous hydration with a solution containing 10% glucose which can reestablish an anabolic state. This can be followed by reintroduction of the patient's usual diet.[2]
Last updated: 2/5/2016

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

Related diseases are conditions that have similar signs and symptoms. A health care provider may consider these conditions in the table below when making a diagnosis. Please note that the table may not include all the possible conditions related to this disease.

Conditions with similar signs and symptoms from Orphanet
Differential diagnoses include multiple acyl-CoA dehydrogenase deficiency (MADD), ethylmalonic encephalopathy and acute ackee fruit intoxication (see these terms).
Visit the Orphanet disease page for more information.

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

  • Orphanet lists European clinical trials, research studies, and patient registries enrolling people with this condition. 
  • The Research Portfolio Online Reporting Tool (RePORT) provides access to reports, data, and analyses of research activities at the National Institutes of Health (NIH), including information on NIH expenditures and the results of NIH-supported research. Although these projects may not conduct studies on humans, you may want to contact the investigators to learn more. To search for studies, enter the disease name in the "Text Search" box. Then click "Submit Query".

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 Short-chain acyl-CoA dehydrogenase deficiency. This website is maintained by the National Library of Medicine.
  • The National Organization for Rare Disorders (NORD) has a report for patients and families about this condition. NORD is a patient advocacy organization for individuals with rare diseases and the organizations that serve them.
  • Save Babies Through Screening Foundation's website has an information page on short-chain acyl-coenzyme A dehydrogenase (SCAD) deficiency. Click on Save Babies Through Screening Foundation to view this information page. 
  • 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.
  • The Muscular Dystrophy Association has developed a resource called "Facts About Myopathies" that discusses commonly asked questions regarding myopathies. Click on the link above to view this information page.

In-Depth Information

  • 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.
  • 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 Short-chain acyl-CoA dehydrogenase deficiency. Click on the link to view a sample search on this topic.

Selected Full-Text Journal Articles

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

  • My daughter has been diagnosed with short-chain acyl-CoA dehydrogenase (SCAD) deficiency. Although her doctors have been helpful, I still have many questions. Can you provide me with more information about this condition? See answer


  1. Short-chain acyl-CoA dehydrogenase deficiency. Genetics Home Reference (GHR). May 2015; http://ghr.nlm.nih.gov/condition/short-chain-acyl-coa-dehydrogenase-deficiency.
  2. Jerry Vockley, MD, PhD. Short-Chain Acyl CoA Dehydrogenase Deficiency (SCAD). National Organization for Rare Disorders (NORD). 2013; http://rarediseases.org/rare-diseases/short-chain-acyl-coa-dehydrogenase-deficiency-scad/.