MYL4 and atrial fibrillation: MYL4 loss-of-function variants have been associated with atrial cardiomyopathy and atrial arrhythmias such as atrial fibrillation (AF) [27, 36–38], demonstrating that although previously not associated with CHD directly, its role in cardiac development and function is important, and thus, could be a plausible candidate gene for CHD.