Carnitine Palmitoyltransferase IA Deficiency

Carnitine palmitoyltransferase IA (CPT IA) deficiency is an inherited disorder in which the body is unable to use certain types of fats for energy. This is due to a deficiency of the enzyme carnitine palmitoyltransferase IA. Onset of symptoms is usually in infancy or childhood, beginning with poor appetite, irritability, fatigue, followed by more serious symptoms of low blood sugar, fever and vomiting. If left untreated, a child with CPT IA can then develop liver failure, seizures, coma leading to sudden death. Appearance of symptoms tends to be episodic and is usually triggered by periods of fasting or illness. Affected individuals are developmentally and cognitively normal between episodes, however recurrent episodes can cause brain damage, resulting in learning problems or intellectual disability. The life expectancy of individuals with CPT IA is not affected if fasting and intense exercise is avoided. CPT IA deficiency is caused by pathogenic variants in the CPT1A gene.

CPT IA deficiency is inherited in an autosomal recessive manner. This type of inheritance requires the presence of two copies of a pathogenic variant in the gene for a person to have the genetic disease. Both parents must be carriers of a pathogenic variant in the gene in order to be at risk to have an affected child. The child must inherit a pathogenic variant from each carrier parent in order to be affected. There is a 1 in 4 chance that a baby will inherit two mutated copies of the gene and be affected when both parents are carriers.

There are generally no signs or symptoms associated with being a carrier for CPT IA deficiency. However, when female carriers get pregnant, they should be monitored for acute fatty liver of pregnancy if the baby is affected with CPT IA deficiency. The risk for a carrier to have a child affected with this condition is increased. Testing of reproductive partners is recommended for carriers of CPT IA deficiency.

CPT IA deficiency is a rare condition. So far, fewer than 50 individuals have been reported with this condition. It is most common in the Hutterite and Inuit populations, where it occurs in 1 in 770 newborns.

Genetics Home Reference: Carnitine palmitoyltransferase I deficiency (http://ghr.nlm.nih.gov/)

OMIM [CARNITINE PALMITOYLTRANSFERASE I DEFICIENCY: 255120] (http://www.ncbi.nlm.nih.gov/omim)
Gene Reviews: Carnitine Palmitoyltransferase 1A Deficiency (http://www.ncbi.nlm.nih.gov/books/NBK1116/)

• Full gene sequencing