Your browser does not support javascript:   Search for gard hereSearch for news-and-events here.

Diseases

Genetic and Rare Diseases Information Center (GARD)

Print friendly version

Primary carnitine deficiency


Other Names for this Disease
  • Carnitine deficiency, systemic, due to defect in renal reabsorption of carnitine
  • Carnitine plasma-membrane transporter deficiency
  • Carnitine transporter deficiency
  • Carnitine uptake defect
  • Carnitine uptake deficiency
More Names
See Disclaimer regarding information on this site. Some links on this page may take you to organizations outside of the National Institutes of Health.

Overview



What is primary carnitine deficiency?

What causes primary carnitine deficiency?

How is primary carnitine deficiency inherited?

How might primary carnitine deficiency be treated?


What is primary carnitine deficiency?

Primary carnitine deficiency is a genetic condition that prevents the body from using certain fats for energy, particularly during periods without food (fasting). The nature and severity of signs and symptoms may vary, but they most often appear during infancy or early childhood and can include severe brain dysfunction (encephalopathy), cardiomyopathy, confusion, vomiting, muscle weakness, and hypoglycemia.[1] Some individuals may only have fatigability in adulthood, or no symptoms at all. This condition is caused by mutations in the SLC22A5 gene and is inherited in an autosomal recessive manner. Treatment and prevention of symptoms typically includes oral L-carnitine supplementation.[2]
Last updated: 7/9/2012

What causes primary carnitine deficiency?

Mutations in the SLC22A5 gene cause primary carnitine deficiency. This gene provides instructions for making a protein called OCTN2 that transports carnitine into cells. Cells need carnitine to bring certain types of fats (fatty acids) into mitochondria, which are the energy-producing centers within cells. Fatty acids are a major source of energy for the heart and muscles. During periods of fasting, fatty acids are also an important energy source for the liver and other tissues.

Mutations in the SLC22A5 gene result in an absent or dysfunctional OCTN2 protein. As a result, there is a shortage (deficiency) of carnitine within cells. This deficiency, as well as potential build-up of fatty acids within the cells, causes the signs and symptoms of the condition.[3]
Last updated: 7/9/2012

How is primary carnitine deficiency inherited?

Primary carnitine deficiency is inherited in an autosomal recessive manner. Individuals have two copies of each gene, one of which is inherited from each parent. For an individual to have an autosomal recessive condition, he/she must have a mutation in both copies of the disease-causing gene. The parents of an affected individual, who each likely have one mutated copy, are referred to as carriers. Carriers typically do not have any signs or symptoms of the condition. When two carriers for an autosomal recessive condition have children together, each child has a 25% (1 in 4) risk to have the condition, a 50% (1 in 2) risk to be a carrier like each of the parents, and a 25% risk to not have the condition and not be a carrier.
Last updated: 7/9/2012

How might primary carnitine deficiency be treated?

Most individuals with primary carnitine deficiency are followed by a metabolic doctor as well as a dietician familiar with this condition. Certain treatments may be advised for some children but not others. Treatment is often needed throughout life. The main treatment for this condition is lifelong use of L-carnitine, which is a natural substance that helps body cells make energy. It also helps the body get rid of harmful wastes. L-carnitine can reverse the heart problems and muscle weakness caused by this condition.[4]

In addition to L-carnitine, infants and young children with primary carnitine 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. But some babies need to eat even more frequently than this. Many teens and adults with this condition can go without food for up to 12 hours without problems. Some children and teens benefit from a low-fat, high carbohydrate diet. Any diet changes should be made under the guidance of a metabolic specialist and/or dietician familiar with this condition. Ask your doctor whether your child needs to have any changes in his or her diet. Other treatments usually need to be continued throughout life.[4]

Infants and children with this condition need to eat extra starchy food and drink more fluids during any illness, even if they may not feel hungry, because they could have a metabolic crisis. Children who are sick often do not want to eat. If they won’t or can’t eat, they may need to be treated in the hospital to prevent serious health problems.[4]
Last updated: 10/17/2011

References
  1. Primary carnitine deficiency. Genetics Home Reference. July 2006; http://www.ghr.nlm.nih.gov/condition/primary-carnitine-deficiency. Accessed 10/17/2011.
  2. Ayman W El-Hattab. Systemic Primary Carnitine Deficiency. GeneReviews. March 15, 2012; http://www.ncbi.nlm.nih.gov/books/NBK84551/. Accessed 7/9/2012.
  3. Primary carnitine deficiency. Genetics Home Reference. July 2006; http://www.ghr.nlm.nih.gov/condition/primary-carnitine-deficiency. Accessed 7/9/2012.
  4. Carnitine transporter deficiency. Screening, Technology, and Research in Genetics (STAR-G). April 2011; http://www.newbornscreening.info/Parents/fattyaciddisorders/Carnitine.html. Accessed 10/17/2011.