TNNI3 and Mitral regurgitation: Five (7.4%) patients in the cTnI-negative group had abnormal findings: one had pre-existing Pompe disease-related hypertrophic cardiomyopathy, one had a ventricular septal defect, one had congestive heart failure with moderate mitral regurgitation and tricuspid regurgitation, and two had mitral valve prolapse.