Subsequent, whole-exome sequencing (WES) gene testing revealed a pathogenic heterozygous variant in <i>LAMP2</i> gene (c.696T>A; p.Cys232Ter), which confirmed the diagnosis of Danon disease.<h4>Conclusion</h4>Genetic testing should be considered in patients who display multiple arrhythmias with LV structural abnormalities of unknown etiology for a possible Danon disease. Here, LAMP2 is linked to Danon disease.