TTN and familial dilated cardiomyopathy: Recent work has elucidated the key pathomechanisms of TTNtv‐DCM: protein studies in over 100 end‐stage failing DCM heart tissues, 22 of them with a TTNtv, suggested that titin haploinsufficiency is present in TTNtv hearts and causes loss of sarcomeres (Figure 2).63, 64