Don’t fight Carnitine-acylcarnitine translocase deficiency alone.
Find your community on the free RareGuru App.Carnitine-acylcarnitine translocase (CACT) deficiency is a disease that prevents the body from converting certain fats called long-chain fatty acids into energy, particularly during periods without food (fasting). Carnitine, a natural substance acquired mostly through the diet, is used by cells to process fats and produce energy. People with this disorder have a faulty transporter (CACT) that disrupts carnitine's role in processing long-chain fatty acids.
There are two forms of carnitine-acylcarnitine translocase deficiency. The most common type is severe and happens in newborns. A milder, less common type happens in older infants and children. Most patients with CACT deficiency have a severe disease presenting within the first 48 hours of life as low blood sugar with ketonic bodies (hypoketotic hypoglycemia), high ammonia (hyperammonemia) levels in the blood, increased heart muscle (cardiomyopathy), and abnormal heart rhythm (arrhythmias), as well as skeletal muscle damage, liver problems, and low temperature (hypothermia). Neurological involvement, seizures, and developmental delay are also present. Rarely, patients present as a sudden infant death. The CACT deficiency is caused by mutations in the SLC25A20 gene. Treatment is done by avoiding fasting and having a low long-chain fat diet with medium chain triglyceride (MCT) supplementation.
Carnitine-acylcarnitine translocase deficiency is a type of fatty acid oxidation disorder.
Source: GARD Last updated on 05-01-20
The signs of carnitine-acylcarnitine translocase (CACT) deficiency usually begin within the first few hours after birth. Seizures, an irregular heartbeat (arrhythmia), and breathing problems are often the first signs of the deficiency. It may also present with extremely low level of ketones (which are products of fat breakdown that are used for energy) and with low blood sugar (hypoglycemia). Together these signs are called "hypoketotic hypoglycemia", which can result in unconsciousness and seizures.
Other signs that are often present include:
In some severe cases of CACT deficiency, infants may present with sudden infant death.
Children with the mild type of CACT deficiency usually start having symptoms before age three and present with episodes of hypoketotic hypoglycemia and hyperammonemia often brought on by fasting and/or by being sick.
Last updated on 05-01-20
80%-99% of people have these symptoms.
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5%-29% of people have these symptoms.
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An unknown % of people have these symptoms.
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Carnitine-acylcarnitine translocase deficiency is caused by mutations in the SLC25A20 gene, which provides instructions for making an enzyme called carnitine-acylcarnitine translocase (CACT), which is essential for fatty acid oxidation (a multistep process that breaks down (metabolizes) fats and converts them into energy). Fatty acid oxidation takes place within mitochondria. A group of fats called long-chain fatty acids must be attached to a substance known as carnitine to enter the mitochondria. CACT's job is to transport them into the mitochondria. CACT 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 do not eat for a stretch of time - like when we miss a meal or when we sleep.
The mutations result in missed or non-functional CACT (CACT deficiency).When the CACT 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 in the body. 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 buildup of harmful substances in the blood.
To better understand these concepts, you may benefit from visiting the Elmhurst College website which offers a virtual animation that explains how fatty acids are transferred from the cytoplasm to the mitochondria.
Last updated on 05-01-20
Genetic testing for carnitine-acylcarnitine translocase deficiency can be done on a blood sample. Genetic testing, also called DNA testing, looks for changes in the pair of genes that cause carnitine- acylcarnitine translocase deficiency. In some affected children, both gene changes can be found. However, in other children, neither or only one of the two gene changes can be found, even though we know they are present. DNA testing is not necessary to diagnose carnitine-acylcarnitine translocase deficiency, however, it can be helpful for carrier testing or prenatal diagnosis.
Last updated on 05-01-20
Carnitine-acylcarnitine translocase (CACT) deficiency is inherited in an autosomal recessive pattern.
Last updated on 05-01-20
Prompt and careful treatment may help prevent or control symptoms in children with mild carnitine-acylcarnitine translocase deficiency.[321 Outcomes seem to correlate better with the absence of cardiac disease. Diagnosis before the occurrence of clinical symptoms and very early treatment, together with good dietary compliance, could lead to a better prognosis, especially in milder clinical cases. However, some children continue to have metabolic crises and other health problems despite treatment. Even with treatment, there is a risk of death, especially in newborns with symptoms.
Last updated on 05-01-20
Treatment includes:
Other treatment options for milder cases with some residual CACT activity may be the administration of statins and fibrates that have been shown to increase the amount of CACT.
When children get sick, parents should call the doctor. Children with CACT 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.
Last updated on 05-01-20
The Screening, Technology, and Research in Genetics (STAR-G) Project was a multi-state collaborative effort to obtain research data, identify strategies, and develop written materials for addressing the financial, ethical, legal and social issues surrounding the use of tandem mass spectrometry for newborn screening. As part of the STAR-G Project, fact sheets on newborn screening disorders have been developed for parents. To view the fact sheet on carnitine acylcarnitine translocase deficiency (CAT), visit the STAR-G link.
Last updated on 04-27-20
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.
Last updated on 04-27-20
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