KCNQ1 and cardiac arrhythmia: He underwent genetic testing, including a comprehensive arrhythmia and cardiomyopathy panel, in April 2013 through GeneDx (Gaithersburg, MD, USA), which confirmed a disease-causing class I variant in KCNQ1 (p.Ala341Gly), a gene with a known association with LQTS type 1.