TNNC1 and atrial fibrillation: Patients with pathogenic variants in MYH7 have an increased risk of developing atrial fibrillation, earlier onset of disease, and more severe form of disease overall than patients with pathogenic variants in MYBPC3. Also, it has been established that HCMP patients with mutations in TNNI3 had shorter life expectancy compared to carriers of mutations in either MYBPC3 or MYH7, while HCMP patients with mutation in TNNC1 had an increased risk of developing a fatal atrial arrhythmia27.