Instituto Valenciano de Microbiología

Masía El Romeral
Ctra. de Bétera a San Antonio Km. 0.3
46117 Bétera (Valencia)
Phone. 96 169 17 02
Fax 96 169 16 37
CIF B-96337217


Acylcarnitine translocase carnitine deficiency of ... (Carnitine acylcarnitine translocase-deficiency) - Gen SLC25A20

Carnitine deficiency-acylcarnitine translocase (CACT) is a disorder that prevents the body use certain fats for energy, particularly during periods of fasting. Usually the signs and symptoms of this disorder begin soon after birth and may include respiratory problems, seizures and arrhythmia. People usually have hypoglycemia and a low concentration of ketones, which are produced during the decomposition of fats and used to produce energy. Together, these signs are called hypoketotic hypoglycemia. Other manifestations may include hyperammonemia, hepatomegaly and cardiomyopathy. Many newborns with the disease do not survive the neonatal period. Some affected individuals have a less severe form of the disease and the signs and symptoms do not occur until early childhood. These people are at risk of liver failure, nerve damage, coma and sudden death.

This process is due to mutations in the SLC25A20 gene (solute carrier family 25 member 20), located on the short arm of chromosome 3 (3p21.31). This gene codes acylcarnitine translocase carnitine (CACT) protein. This protein is essential for the oxidation of a multistep process that metabolizes fats and fatty acids into energy. Oxidation of fatty acids occurs in the mitochondria. Fatty acids long chain must be attached to a molecule of carnitine to enter the mitochondria. Once these fatty acids bind with carnitine, CACT protein transports them to the mitochondria. Fatty acids are an important source of energy for the heart and muscles. During periods of fasting, the fatty acids are also an important source of energy for the liver and other tissues.

They have identified at least 27 mutations in the gene SLC25A20 in people with carnitine-acylcarnitine deficiency translocase (CACT). Although these mutations change the structure of the protein CACT different ways, all cause a deficiency of the protein. Without enough functional protein CACT, fatty acids long chain can not be transported to mitochondria. Consequently, these fatty acids are converted to energy. A decrease in energy production can lead to some of the characteristics of CACT deficiency, as hypoketotic hypoglycemia. In addition, fatty acids and long - chain acylcarnitines can also accumulate in the cells and damage the liver, heart and muscles. This accumulation causes the other signs and symptoms of the disease.

This disease is inherited in an autosomal recessive pattern, that is, both copies of the gene in every cell must have mutations for alteration is expressed. The parents of an individual with an autosomal recessive disease have a copy of the mutated gene, but usually show no signs and symptoms of the disease.

Tests in IVAMI: in IVAMI perform detection of mutations associated with carnitine deficiency acylcarnitine translocase-by complete PCR amplification of the exons of the SLC25A20 gene, and subsequent sequencing.

Samples recommended: EDTA blood collected for separation of blood leukocytes, or impregnated sample card with dried blood (IVAMI may mail the card to deposit the blood sample).