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Disease Profile

SCOT 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.

<1 / 1 000 000

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)

Succinyl-CoA:3-oxoacid CoA transferase deficiency; Ketoacidosis due to SCOT deficiency; Succinyl-CoA acetoacetate transferase deficiency;


Congenital and Genetic Diseases; Metabolic disorders


SCOT deficiency is a metabolic disease that is caused by reduced or missing levels of an enzyme called succinyl-CoA:3-ketoacid CoA transferase (SCOT). This enzyme is necessary for the body to use ketones. Ketones are substances produced in the liver when fats are broken down. Ketones are an important source of energy, especially when there is a shortage of carbohydrates (sugar). SCOT deficiency is characterized by episodes of ketoacidosis (build-up of ketones in the body).[1] Symptoms of ketoacidosis may vary but can include trouble breathing, poor feeding, vomiting, and lethargy. In some cases, the symptoms can progress to include loss of consciousness and a coma. In between these episodes, individuals with SCOT deficiency do not have any symptoms.[1]

SCOT deficiency is caused by mutations (changes) in the OXCT1 gene. The disease is inherited in an autosomal recessive manner.[2] SCOT deficiency can be diagnosed by ruling out other causes of ketoacidosis and measuring the level of SCOT enzyme. Genetic testing of the OXCT1 gene can be used to confirm the diagnosis.[1] Immediate treatment of ketoacidotic crises is critical. Treatment options include IV fluids such as glucose and sodium bicarbonate. Frequent meals and eating a diet low in fats is important to reduce the frequency of ketoacidotic crises.[1]


Symptoms of SCOT deficiency include episodes of ketoacidosis (build-up of ketones in the body). These episodes are often brought on by physical stress, fasting, or illness. The first episode often occurs in newborns or infants between 6-20-months-old.[1] This is because this is often a time when babies begin to eat less frequent meals. Ketones do not need to be broken down by the body until the storage of glucose (sugars) is low. This often happens after about 4 hours of fasting. However, in some cases, babies with SCOT deficiency may have a ketoacidotic episode within the first few days of life.[3]

Symptoms of ketoacidosis may vary but can include rapid breathing (tachypnea), poor feeding, vomiting, and lethargy. In some cases, the symptoms can progress to include seizures, loss of consciousness and a coma.[1][3] The severity of symptoms during ketoacidotic crises can vary. Between crises, individuals with SCOT deficiency have no symptoms. If the disease is properly treated with diet, normal growth and development are expected.[1]

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:
Percent of people who have these symptoms is not available through HPO
Autosomal recessive inheritance
Elevated urinary 3-hydroxybutyric acid
Episodic ketoacidosis
Neonatal onset
Increased respiratory rate or depth of breathing
Throwing up


SCOT deficiency is caused by mutations (changes) to the OXCT1 gene. This gene provides the body with instructions for how to create an enzyme called succinyl-CoA:3-ketoacid CoA transferase (SCOT). The SCOT enzyme helps the body break down ketones to be used for energy. When there are mutations in the OXCT1 gene, the body does not make enough of the SCOT enzyme. This causes the body to be unable to break down ketones. When ketones cannot be broken down, they begin to accumulate in the blood and the body does not have enough energy. This causes the symptoms of SCOT deficiency.[3]

It is especially important for the body to be able to break down ketones when there is not other energy available to the body through glucose (sugars). Ketones are most frequently used for energy during times of fasting between meals, illness, or stress. These are the times when symptoms of SCOT deficiency are most likely to occur.[3]


SCOT deficiency is diagnosed when a child presents with symptoms of the disease during a ketoacidotic crisis. A healthcare provider will then typically complete a series of laboratory tests to rule out other diseases that can cause similar symptoms. Levels of SCOT enzyme can be measured by testing the cells of the skin (fibroblasts). If these enzyme levels are low, it indicates that a child has SCOT deficiency. Genetic testing of the OXCT1 gene can be used to confirm the diagnosis.[1]

Testing Resources

  • Orphanet lists international laboratories offering diagnostic testing for this condition.


    The treatment for SCOT deficiency is based on trying to avoid ketoacidotic crises, as these are the only times that symptoms of the disease occur. Because ketoacidotic crises occur when all of the glucose from a meal is broken down, it is important for people with SCOT deficiency to eat frequent meals with large amounts of carbohydrates. It is also important for people with SCOT deficiency to avoid eating food with high fat content. Doctors may recommend that people with the disease avoid highprotein meals as well. Individuals with SCOT deficiency can monitor levels of ketones in the urine in order to make sure they are not too high. Oral sodium bicarbonate supplements can be used in times of stress, such as an illness, to make sure that the body is receiving enough energy from other forms.[1] 

    If a ketoacidotic crisis does occur, it is important that people with SCOT deficiency receive treatment right away. People with this disease typically respond well to IV infusions of glucose and sodium bicarbonate during times of ketoacidotic crisis.[1]

    Management Guidelines

    • Orphanet Emergency Guidelines is an article which is expert-authored and peer-reviewed that is intended to guide health care professionals in emergency situations involving this condition.


      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

          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 SCOT deficiency. Click on the link to view a sample search on this topic.

            Selected Full-Text Journal Articles


              1. Fukao T. Succinyl-CoA : 3-ketoacid CoA transferase (SCOT deficiency). Orphanet Encyclopedia. September 2004; https://www.orpha.net/data/patho/GB/uk-scot.pdf.
              2. Succinyl-CoA:3-Oxoacid-CoA Transferase Deficiency; SCOTD. Online Mendelian Inheritance in Man. May 22, 2015; https://www.omim.org/entry/245050.
              3. Succinyl-CoA:3-ketoacid CoA transferase deficiency. Genetics Home Reference. December 2011; https://ghr.nlm.nih.gov/condition/succinyl-coa3-ketoacid-coa-transferase-deficiency.
              4. Sasai H, Aoyama Y, Otsuka H, Abdelkreem E, Naiki Y, Kubota M, Sekine Y, Itoh M, Nakama M, Ohnishi H, Fujiki R, Ohara O, and Fukao T. Heterozygous carriers of succinyl-CoA:3 oxoacid CoA transferase deficiency can develop severe ketoacidosis. Journal of Inherited Metabolic Disease. July 10, 2017; https://www.ncbi.nlm.nih.gov/pubmed/28695376.
              5. Fukao T. Succinyl-CoA:3-ketoacid CoA transferase deficiency. Orphanet. September 2013; https://www.orpha.net/consor/cgi-bin/OC_Exp.php?lng=en&Expert=832.
              6. Fukao T, Sass JO, Kursula P, Thimm E, Wendel U, Ficicoglu C, Monastiri K, Guffon N, Baric I, Zabot MT, and Kondo N. Clinical and molecular characterization of five patients with succinyl-CoA:3-ketoacid CoA transferase (SCOT) deficiency. Biochimica et Biophysica Acta. May 2011; 1812(5):619-624. https://www.ncbi.nlm.nih.gov/pubmed/21296660.

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