Myopathic carnitine palmitoyltransferase II deficiency (myopathic CPTII) is a fatty acid oxidation disorder, which means the body cannot convert fats into useful energy. The resulting symptoms begin during childhood and include muscle pain and weakness. This is because the body begins breaking down muscle (rhabdomyolysis) in order to obtain the energy that it isn’t getting from fatty acids.
CPTII is caused by a mutation (change) to the CPT2 gene. This gene provides the body with an instruction to make a protein called carnitine palmitoyltransferase II (CPII). This protein removes a substance called carnitine from fatty acids in order to break them down and create energy. If there is a mutation to the CPT2 gene, carnitine is not removed from fatty acids and less energy is produced. People affected by myopathic CPTII produce more of the enzyme required to break down fatty acids than other forms of CPTII, so it is the least severe form. CPTII is an autosomal recessive disease, meaning that a person affected by the disease has two mutated copies of the CPT2 gene. A person with only one mutated copy of the gene is called a carrier. Any child of two carriers has a one in four chance of having the disease.
CPTII can be diagnosed before birth by testing for levels of fatty acids in the blood and measuring CPII enzyme activity. Treatments such as dietary changes and avoiding exercise have been successful in preventing the symptoms of the disease. Many babies are screened for CPTII so that treatment can begin early, but the conditions included in newborn screening vary by state. For more information, visit Baby’s First Test.Talk with your doctor to determine which treatment options are best for your child. Genetic counselors and support groups are also a good source of information.