CPT® Code 81281

Deleted

Long QT syndrome gene analyses (eg, KCNQ1, KCNH2, SCN5A, KCNE1, KCNE2, KCNJ2, CACNA1C, CAV3, SCN4B, AKAP, SNTA1, and ANK2); known familial sequence variant

Molecular genetic testing is a critical procedure used to identify specific gene mutations that are responsible for long QT syndrome (LQTS), a rare and inherited cardiac condition characterized by delayed repolarization of the heart. This condition is particularly sensitive to adrenergic stimulation, which can occur during activities such as exercise or excitement. The presence of certain mutations in genes associated with LQTS can lead to a prolongation of the ventricular action potential and an extended QT interval on an electrocardiogram (ECG). Individuals diagnosed with LQTS face an increased risk of developing irregular heart rhythms, experiencing cardiac palpitations, having syncopal episodes (fainting), and potentially suffering sudden cardiac death due to ventricular fibrillation. The genetic mutations associated with LQTS can be inherited in an autosomal dominant or autosomal recessive manner. In some cases, the more severe recessive phenotypes may also be linked to additional physical anomalies such as syndactyly, which is characterized by fused fingers or toes, and congenital neural deafness. The testing process involves a full sequence analysis, which compares segments of genes to identify similarities or differences, thereby elucidating relationships among them. This analysis also examines intrinsic features of the genes to locate active sites and post-translational modification sites, as well as the distribution of introns, exons, and regulatory elements. Genetic markers are identified through the detection of point mutations or single nucleotide polymorphisms (SNPs). The most prevalent mutation associated with LQTS, known as LQT1, is located on the KCNQ1 gene found on chromosome 11 and is present in approximately 30-35% of individuals diagnosed with this syndrome. The CPT® Code 81281 specifically pertains to the analysis of LQTS genes for known familial sequence variants. When a gene mutation causing LQTS or a related syndrome is identified in an individual, it is recommended that all first-degree relatives undergo molecular genetic testing. This testing can help identify common or familial variants among blood relatives and assess the risk factors for those who may carry the gene mutation. Additionally, other CPT® codes, such as 81280 and 81282, are used for full sequence analysis and for identifying deletion or duplication variants, respectively, further enhancing the understanding and management of long QT syndrome.