Carnitine is a nutrient that your body needs to break down the fats in your diet and use them to make energy. Some children are born with a genetic condition called primary carnitine deficiency. People with this disorder lack the ability to properly use the carnitine in their bodies; as a result, they can develop a form of heart disease called cardiomyopathy.
The Basics
Major sources of dietary carnitine include pork, beef, fish, chicken, milk and other dairy products. You can also get smaller amounts of the nutrient from whole grains and various fruits and vegetables. In addition to dietary sources, your body gets carnitine from internal supplies generated in your kidneys and liver. You rely on carnitine to transport substances called fatty acids to structures in your cells called mitochondria, which produce energy by burning, or oxidizing, these acids. People with primary carnitine deficiency have a defect in a substance called carnitine transporter protein OCTN2, and can't deliver the required amount of fatty acids to their mitochondria.
Deficiency and Cardiomyopathy
Like other organs in your body, your heart relies on fatty acid burning in mitochondria to provide its tissues with energy. Without this energy, heart tissue alters its normal consistency and becomes thicker, enlarged or unusually rigid; it sometimes also develops scarring. Doctors refer to this collection of destructive changes as cardiomyopathy. The most common forms of this disorder are called dilated, restrictive and hypertrophic cardiomyopathy; another rarer form is called arrhythmogenic right ventricular dysplasia. People with primary carnitine deficiency most frequently develop dilated cardiomyopathy, according to a study published in 2008 in "Molecular Genetics and Metabolism."
Dilated Cardiomyopathy
People with dilated cardiomyopathy develop destructive tissue changes in both the upper and lower chambers of the heart. The disorder, which frequently starts in the heart's main pumping chamber, triggers a thinning and stretching of the muscle tissue, which eventually leads to enlargement of the heart's chambers. In turn, this enlargement reduces the heart's pumping efficiency and makes it grow weaker over time. Eventually people with dilated cardiomyopathy can develop an incurable condition called heart failure.
Considerations
If people with primary carnitine deficiency don't receive treatment for their condition, they will die, Oregon State University's Linus Pauling Institute reports. The standard treatment for the disorder is supplemental doses of a form of carnitine called L-carnitine; L-carnitine therapy typically relieves the effects of cardiomyopathy and also reverses any muscle weaknesses associated with primary deficiency. Another form of carnitine deficiency, called secondary carnitine deficiency, can stem from either hereditary or acquired causes. Its main manifestations are low blood levels of carnitine and alterations in the ratio between carnitine and a related substance called acylcarnitine. Consult your doctor for more information on cardiomyopathy and primary and secondary carnitine deficiencies.
References
- University of Maryland Medical Center: Carnitine (L-Carnitine)
- "Molecular Genetics and Metabolism": Cardiomyopathy and Carnitine Deficiency; Amat di San Filippo, Taylor, et al.; March 11, 2008
- Oregon State University - Linus Pauling Institute: L-Carnitine; Jane Higdon, Ph.D.; October 2002
- National Heart Blood and Lung Institute: Cardiomyopathy (Pages 1 and 2)
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