Carnitine-acylcarnitine translocase deficiency is a rare, autosomal recessive

metabolic disorder A metabolic disorder is a disorder that negatively alters the body's processing and distribution of macronutrients, such as proteins, fats, and carbohydrates. Metabolic disorders can happen when abnormal chemical reactions in the body alter t ...

that prevents the body from converting long-chain fatty acids into energy, particularly during periods without food. 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 enzyme that prevents long-chain fatty acids from being transported into the innermost part of the mitochondria for processing.

Presentation

The signs of carnitine-acylcarnitine translocase deficiency usually begin within the first few hours of life.

Seizure An epileptic seizure, informally known as a seizure, is a period of symptoms due to abnormally excessive or synchronous neuronal activity in the brain. Outward effects vary from uncontrolled shaking movements involving much of the body with l ...

s, an irregular heartbeat, and breathing problems are often the first signs of this disorder. This disorder may also cause extremely low levels of ketones (products of fat breakdown that are used for energy) and low blood sugar (

hypoglycemia Hypoglycemia, also called low blood sugar, is a fall in blood sugar to levels below normal, typically below 70 mg/dL (3.9 mmol/L). Whipple's triad is used to properly identify hypoglycemic episodes. It is defined as blood glucose bel ...

). Together, these two signs are called hypoketotic hypoglycemia. Other signs that are often present include ammonia in the blood (

hyperammonemia Hyperammonemia is a metabolic disturbance characterised by an excess of ammonia in the blood. It is a dangerous condition that may lead to brain injury and death. It may be primary or secondary. Ammonia is a substance that contains nitrogen. It i ...

), an enlarged liver (

hepatomegaly Hepatomegaly is the condition of having an enlarged liver. It is a non-specific medical sign having many causes, which can broadly be broken down into infection, hepatic tumours, or metabolic disorder. Often, hepatomegaly will present as an abdo ...

), heart abnormalities ( cardiomyopathy), and muscle weakness. This disorder can cause sudden infant death.

Pathophysiology

Mutations in the '' SLC25A20''

gene In biology, the word gene (from , ; "... Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a b ...

lead to the production of a defective version of an enzyme called carnitine-acylcarnitine translocase. Without this enzyme, long-chain fatty acids from food and fats stored in the body cannot be 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. Free long-chain fatty acids or those that are joined with carnitine can affect the electrical properties of cardiac cells causing an irregular heart beat ( arrhythmia, which can lead to cardiac arrest). Fatty acids may also build up in tissues and can damage the heart, liver, and muscles, and cause more serious complications. This condition has an autosomal recessive inheritance pattern, which means the defective gene is located on an autosome, and two copies of the gene - one from each parent - must be inherited to be affected by the disorder. The parents of a child with an autosomal recessive disorder are carriers of one copy of the defective gene, but are usually not affected by the disorder.

Diagnosis

Treatment

References

''This article incorporates public domain text fro
The U.S. National Library of Medicine
'

External links