Succinyl-CoA: 3-Oxoacid-CoA Transferase Deficiency

What else is it called?

  • Ketoacidosis due to SCOT Deficiency
  • SCOT Deficiency
  • Succinyl-CoA Acetoacetate Transferase Deficiency

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What causes it?

SCOT Deficiency is an inherited metabolic disorder caused by a problem in the OXCT1 gene. This gene provides instructions for an enzyme called succinyl-CoA:3-ketoacid CoA transferase (SCOT). The SCOT enzyme is needed to enable your body to break down ketones efficiently. Ketones are made in the liver when your body breaks down fats. They are needed as an energy source, especially during long periods without food or times when your body needs more energy.

If you have SCOT Deficiency, the enzyme is missing, or you do not produce enough of it. Your body is unable to break down the ketones and therefore you cannot use them as an energy source, reducing energy production and causing the ketones build up in the blood. This leads to episodes of ketoacidosis, sometimes called ketoacidotic attacks.

How common is it?

We do not know how common this condition is. There have been over 30 cases reported.

What are the signs and symptoms?

This condition is characterised by episodes of ketoacidosis, or ketoacidotic attacks. The term ‘ketoacidosis’ means ‘a build up of ketones in the body’. Symptoms of ketoacidosis include:

  • Breathing problems
  • Poor feeding
  • Vomiting
  • Lethargy
  • Seizures (occasionally)

If left untreated, these episodes can progress to a coma. Severe attacks can be fatal. The frequency of attacks varies.

If you have this condition you are likely to always have a high level of ketones in your blood. However, the level can become too high if you have an infection, illness, or go for long periods without food, and this can trigger an attack. The first attack usually occurs within the first few days following birth. However, symptoms can begin anytime within the first year of life. Other than poor feeding and failure to grow or gain weight prior to diagnosis, there are no other symptoms other than ketoacidosis. In some rare cases, heart problems may occur.

How is it diagnosed?

This condition can be diagnosed using specialised blood and urine tests. Enzyme activity can be measured using blood cells. Genetic testing can confirm the diagnosis. Prenatal diagnosis may be available if there is a known history of the condition in the family.

Can it be treated?

There is no cure for this condition. Treatment is lifelong and includes the avoidance of triggers which can cause attacks. This involves eating regular meals and following a low-fat diet. If an attack occurs, immediate treatment is needed which includes intravenous fluids. You will be given an emergency regimen to follow in times of illness or if symptoms of an attack begin.

Do my family need to be tested?

Humans have chromosomes composed of DNA. Genes are pieces of DNA that carry the genetic instruction. Each chromosome may have several thousand genes. We inherit particular chromosomes from the egg of the mother and sperm of the father. The genes on those chromosomes carry the instructions that determine a person’s characteristics, which are a combination of the parents.

This is an inherited condition. There is nothing that could have been done to prevent it.

Everyone has a pair of genes that are needed to produce the SCOT enzyme. If you have this condition, neither of these genes works correctly. You will inherit one non-working gene from each parent.

Parents of children with this condition are known as carriers. Carriers do not have the disorder because the other gene of this pair is working correctly.

When both parents are carriers, in each pregnancy the risk to the baby is as follows:

  • 25% chance (1 in 4) of developing the condition
  • 50% chance (1 in 2) for the baby to be a carrier
  • 25% chance (1 in 4) for the baby to have two working genes and neither have the condition, nor be a carrier

Relevant Organisations


References are available on request. Please contact Helen Morris by phoning 0845 241 2173 or emailing [Resource Library No: SFKB14].

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