CPT® Code 81465

Whole mitochondrial genome large deletion analysis panel (eg, Kearns-Sayre syndrome, chronic progressive external ophthalmoplegia), including heteroplasmy detection, if performed

The CPT® Code 81465 refers to a comprehensive molecular genetic testing procedure that focuses on the whole mitochondrial genome to identify large deletion mutations in mitochondrial DNA (mtDNA). The mitochondrial genome is a circular DNA structure that contains 37 essential genes, all of which play a critical role in mitochondrial function. These genes can be affected by various types of mutations, including point mutations, deletions, duplications, or complex rearrangements. Mitochondrial disorders, which arise from abnormalities in mtDNA, exhibit a heterogeneous nature and are inherited through the maternal line. These disorders predominantly impact tissues with high energy demands, such as muscles and nerves, and can manifest as multi-systemic issues, particularly in pediatric populations. The clinical presentation of mitochondrial disorders can vary significantly among family members who share the same mutation, highlighting the complexity of these conditions. Unlike nuclear DNA (nDNA), where mutations can exist in a limited number of copies, mtDNA mutations can occur in varying proportions across the total organelle, a phenomenon known as heteroplasmy. The severity of symptoms associated with mitochondrial diseases is closely linked to the degree of heteroplasmy; a higher degree of heteroplasmy typically correlates with more severe clinical manifestations. Notable disorders associated with large deletion mutations in mtDNA include Kearns-Sayre syndrome (KSS) and chronic progressive external ophthalmoplegia (CPEO). The testing process involves analyzing samples from blood, skin, or other tissues to detect large deletion mutations in the whole mitochondrial genome. This is accomplished through gel electrophoresis, followed by the localization of the identified deletions using next-generation sequencing (NGS).