Carnitine is an important nutrient that the body uses to process fats and produce energy. It plays an important role in getting fatty acids into cells to use for energy. Carnitine is especially important for certain cells, such as muscle cells. Carnitine is made in the liver and kidney and is stored in the heart and skeletal muscles. You also get carnitine through some of the foods you eat. Carnitine deficiency is a rare disorder when not enough of carnitine is available to cells in the body. This deficiency prevents the body from processing certain fats into energy. The buildup of fatty acids in cells damages the liver, muscles, and heart. Carnitine deficiency can happen in children and adults of all ages and all ethnic backgrounds.
There are two types of carnitine deficiency: primary and secondary.
Primary carnitine deficiency is a genetic (inherited) disorder of the carnitine transporter system. It is caused by an abnormal gene. The gene causes a problem with a protein that carries carnitine into cells from the blood. Primary carnitine deficiency affects males and females in equal numbers and strikes an estimated one in every 142,000 newborns in the United States. Babies and children tend to show signs and symptoms in the first few years of life. These signs and symptoms can include brain dysfunction, trouble eating, muscle weakness, enlarged liver, tiredness, confusion, low blood sugar, and heart problems.1
Secondary carnitine deficiencies are more common than primary deficiencies. Secondary carnitine deficiencies include both genetic and other non-genetic conditions that result in a decrease in carnitine levels but are not due to primary carnitine deficiency. Different health problems can lower the levels of carnitine in the blood. They may do this by increasing the amount eliminated in urine; or they may cause the body to absorb less carnitine from food. Signs and symptoms of secondary carnitine deficiency include muscle weakness, tiredness, low blood sugar, and heart issues. Carnitine deficiency also occurs in patients who are on dialysis to treat severe kidney disease. If your kidneys no longer remove enough wastes and fluid from your blood to keep you healthy, a special machine, called a dialysis machine can replace kidney functions when your kidneys no longer work. The dialysis machine removes components including carnitine from your blood, leading to carnitine deficiency. Certain conditions common in patients on dialysis, such as feeling tired, muscle weakness and heart issues may be related to abnormal carnitine levels. 1,2
