An international, multicentered evidence-based reappraisal of genes reported to cause congenital long QT syndrome

Background: Long QT syndrome (LQTS) is the first described and most common inherited arrhythmia. Over the last 25 years, multiple genes have been reported to cause this condition and are routinely tested in patients. Due to dramatic changes in our understanding of human genetic variation, reappraisal of reported genetic causes for LQTS is required. Methods: Utilizing an evidence-based framework, three gene curation teams blinded to each other’s work scored the level of evidence for 17 genes reported to cause LQTS. A Clinical Domain Channelopathy Working Group provided a final classification of these genes for causation of LQTS following assessment of the evidence scored by the independent curation teams. Results: Of 17 genes reported as being causative for LQTS, 9 (AKAP9, ANK2, CAV3, KCNE1, KCNE2, KCNJ2, KCNJ5, SCN4B, SNTA1) were classified as having limited or disputed evidence as LQTS-causative genes. Only three genes (KCNQ1, KCNH2, SCN5A) were curated as definitive genes for typical LQTS. Another four genes (CALM1, CALM2, CALM3, TRDN) were found to have strong or definitive evidence for causality in LQTS with atypical features, including neonatal atrio-ventricular block. The remaining gene (CACNA1C) had moderate level evidence for causing LQTS. Conclusions More than half of the genes reported as causing LQTS have limited or disputed evidence to support their disease causation. Genetic variants in these genes should not be used for clinical-decision making, unless accompanied by new and sufficient genetic evidence. The findings of insufficient evidence to support gene-disease associations may extend to other disciplines of medicine and warrants a contemporary evidence-based evaluation for previously reported disease-causing genes to ensure their appropriate use in precision medicine