Interestingly, DCM-causing TTNtv are clustered in the clinically relevant A-band region of the gene whereas TTNtv in reference and healthy individuals are clustered more in the I-band region where they may be spliced out, due to the usage of an alternative promoter, from mature long TTN isoforms resulting in minimal or no functional consequences11. This evidence concerns the gene TTN and familial dilated cardiomyopathy.