Algorithm for genetic test results in congenital long QT syndrome (LQTS) gene

This algorithm presents an approach to evaluating an individual who has genetic testing as the first result. A more common scenario is a clinical finding (symptoms or abnormal ECG) that is further evaluated using genetic testing. The three major congenital LQTS genes are KCNQ1, KCNH2, and SCN5A. Other genes that are less commonly seen in congenital LQTS are discussed in UpToDate. A finding of a pathogenic or likely pathogenic variant (PV or LPV) in one of these genes is considered a positive result, as long as appropriate quality controls have been used in a Clinical Laboratory Improvement Amendments (CLIA)-certified laboratory. Refer to UpToDate for important caveats regarding review and interpretation of genetic test results, and for details of the full evaluation for congenital LQTS and other hereditary heart rhythm disorders.