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Description:The carnitine palmitoyltransferase (CPT) 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 for energy production. The CPT I isozymes (CPT1A and CPT1B) are located in the mitochondrial outer membrane, whereas CPT II is located in the inner mitochondrial membrane. CPT1 catalyzes the esterification of acyl-CoA to form acyl-carnitine, the rate limiting step of mitochondrial fatty acid oxidation. The acylcarnitines are then transferred to the matrix side of the inner mitochondrial membrane through their uptake by carnitine/acylcarnitine translocase (CACT, test number 3435), followed by the reconversion to acyl-CoA by CPT2 (test code 3160). CPT1A is predominantly expressed in liver, and CPT1B (test code 3370) is predominantly expressed in skeletal muscle. They are encoded by different genes. While more than several hundred families with CPT2 deficiencies are known, less than 50 families with a CPT1A deficiency have been reported. CPT1A deficiency is a rare autosomal recessive disorder characterized by severe episodes of hypoketotic hypoglycemia, usually triggered by fasting or illness, and beginning in early childhood. Transient hepatomegaly and acute liver failure have also been reported. Human CPT1A gene is mapped to chromosome 11q13. It contains 20 exons and encodes for a protein of 773 amino acids. Up-to-date, at least 25 different mutations have been reported. Reasons for Referral:
Testing Methodology:The exons and flanking intron regions of CPT1A gene are PCR amplified and sequenced in both forward and reverse directions. Specimen Requirements:Blood: EDTA (purple-top) tubes: Adult: 3 cc; Child and Infant: 3 cc Turnaround Time:2-4 weeks CPT Codes and Prices:
Index: 83891, 83898x20, 83904x40,
83912, 83894x2 Shipping InformationForms:>> Gene Sequencing Requisition Test Codes:Index: 3365 |