Atypical presentation of Andersen-Tawil syndrome: heart failure with reduced ejection without periodic paralysis or dysmorphic features

Andersen-Tawil syndrome (ATS) can present with heart failure with reduced ejection fraction, even without the typical triad of periodic paralysis, dysmorphic features and arrhythmias. Early genetic testing is essential for confirming ATS, especially in atypical cases with unexplained heart failure or arrhythmias.ATS has incomplete penetrance so it may present without the typical features, making diagnosis challenging and requiring a high suspicion in cases with unexplained arrhythmias or family history of sudden cardiac death.