Genetic testing for HCM is also recommended when there is clinical suspicion of syndromic presentations, such as LAMP2 (Danon disease as phenocopy; genetype caracteristics with environmental impact), GLA (Fabry disease), PRKAG2 (glycogen storage disease), TTR (Transthyretin amyloidosis), GAA (Pompe disease), and others, as these results can influence therapeutic decisions, for example, aggressive management for Danon disease or enzyme replacement therapy for Fabry disease [33,34,35,36,37]. Here, TTR is linked to Danon disease.