Carnitine-acylcarnitine translocase deficiency
- CACT deficiency
Your QuestionMy son may have carnitine-acylcarnitine translocase deficiency. Can you provide me with information about this condition?
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Questions on this page
- What is carnitine-acylcarnitine translocase deficiency?
- How common is carnitine-acylcarnitine translocase deficiency?
- What are the signs and symptoms of carnitine-acylcarnitine translocase deficiency?
- What causes carnitine-acylcarnitine translocase deficiency?
- What genes are associated with carnitine-acylcarnitine translocase deficiency?
- How is carnitine-acylcarnitine inherited?
- Is there genetic testing available for carnitine-acylcarnitine translocase deficiency?
- Can carnitine-acylcarnitine translocase deficiency be identified by any other means?
- How might carnitine-acylcarnitine translocase deficiency be treated?
- What is the prognosis for children with carnitine-acylcarnitine translocase deficiency?
Children with the mild type of carnitine-acylcarnitine translocase deficiency usually start having symptoms before age three. They are at risk to have episodes of metabolic crisis, but usually do not have heart problems.
Carnitine-acylcarnitine translocase deficiency occurs when an enzyme, called "carnitine-acylcarnitine translocase" (CAT), is either missing or not working properly. This enzyme's job is to help change certain fats in the food we eat into energy. It also helps to break down fat already stored in the body.
Energy from fat keeps us going whenever our bodies run low of their main source of energy, a type of sugar called glucose. Our bodies rely on fat for energy when we don't eat for a stretch of time - like when we miss a meal or when we sleep.
When the CAT normal enzyme is missing or not working well, the body cannot use fat for energy, and must rely solely on glucose. Although glucose is a good source of energy, there is a limited amount available. Once the glucose has been used up, the body tries to use fat without success. This leads to low blood sugar, called hypoglycemia, and to the build up of harmful substances in the blood.
Mutations in the SLC25A20 gene lead to the production of a defective version of carnitine-acylcarnitine translocase. A shortage of functional transporters prevents long-chain fatty acids from food and fats stored in the body from being broken down and processed. As a result, these fatty acids are not converted into energy, which can lead to characteristic signs and symptoms of this disorder, such as weakness, hypoglycemia, and an irregular heartbeat. Excess long-chain fatty acids, with or without carnitine attached to them, can affect the electrical properties of heart (cardiac) cells. This abnormal accumulation of fatty acids can cause heart damage and an irregular heart beat that can lead to cardiac arrest. Fatty acids may also build up in other tissues and can damage the liver and muscles, resulting in serious, sometimes life-threatening, complications.
Aggressive treatment of hypoglycemia, hyperammonemia and prevention of lipolysis (the breakdown of fat stored in fat cells) in the newborn may be lifesaving. Infants and young children with carnitine-acylcarnitine translocase deficiency need to eat frequently to prevent a metabolic crisis. In general, it is often suggested that infants be fed every four to six hours, although some babies need to eat even more frequently than this. It is important that infants be fed during the night. They may need to be woken up to eat if they do not wake up on their own. Sometimes a low-fat, high carbohydrate diet is advised. Carbohydrates give the body many types of sugar that can be used as energy. In fact, for children needing this treatment, most food in the diet should be carbohydrates (bread, pasta, fruit, vegetables, etc.) and protein (lean meat and low-fat dairy food). Some children may be helped by taking L-carnitine. This is a safe and natural substance that helps body cells make energy. It also helps the body get rid of harmful wastes. However, supplementation with carnitine remains controversial, as its efficacy remains unknown. Medium Chain Triglyceride oil (MCT oil) is sometimes used as part of the food plan for people with carnitine-acylcarnitine translocase deficiency. This special oil has medium chain fatty acids that people with carnitine-acylcarnitine translocase deficiency can use in small amounts for energy.
You may be instructed to call your child's doctor at the start of any illness. Children with carnitine-acylcarnitine translocase deficiency need to eat extra starchy food and drink more fluids during any illness (even if they may not feel hungry) or they could develop a metabolic crisis.
- Carnitine-acylcarnitine translocase deficiency. Genetics Home Reference. August 2006; http://ghr.nlm.nih.gov/condition=carnitineacylcarnitinetranslocasedeficiency. Accessed 4/4/2008.
- Carnitine-acylcarnitine translocase deficiency. Screening, Technology and Research in Genetics. October 5, 2007; http://www.newbornscreening.info/Parents/fattyaciddisorders/CAT.html. Accessed 4/4/2008.
- SLC25A20. Genetics Home Reference (GHR). August 2006; http://ghr.nlm.nih.gov/gene=slc25a20. Accessed 4/6/2008.
- Copeland S, Tuerck J, Paradise L. Carnitine-Acylcarnitine Translocase Deficiency. Oregon Department of Human Services Newborn Screening. http://www.oregon.gov/DHS/ph/nbs/docs/carnitinetranslocase.pdf. Accessed 4/4/2008.