| Description: |
Carnitine palmitoyltransferase enzyme system, in conjunction with acyl-CoA synthetase and carnitine/acylcarnitine translocase, provides the mechanism whereby long chain fatty acids are transferred from the cytosol to the mitochondrial matrix to undergo beta-oxidation. The CPTI isozymes (CPTIA and CPTIB) are located in the mitochondrial outer membrane and are detergent-labile, whereas CPTII is located in the inner mitochondrial membrane and is detergent-stable. CPTII deficiency has three forms of clinical presentations: lethal neonatal form, severe infantile hepatocardiomuscular form, and the mild, adult onset myopathic form. The former two are characterized by reduced serum concentration of total and free carnitine, increased serum concentrations of lipids and long-chain acylcarnitines, hypoketotic hypoglycemia with severe multisystemic diseases including liver failure, cardiomyopathy, seizures, and early death. The late onset myopathic form is characterized by exercise-induced muscle pain and weakness, sometimes associated with myoglobinuria. CPTII deficiency is caused by mutations in CPT2 gene. The diagnosis of CPTII deficiency is usually made by the detection of reduced CPT enzyme activity in skeletal muscle homogenates or cultured skin fibroblasts. However, definitive diagnosis is achieved by DNA analysis of the CPT2 gene. The DNA diagnosis provide a noninvasive means for a rapid and definitive diagnosis of CPTII deficiency. The CPT2 gene contains 5 coding exons and is located on chromosome 1p32. |
