The frameshift variant p.Arg69Alafs* is the most common loss-of-function mutation reported in TNNI3 homozygous DCM patients (9 out of 16 families), possibly because of the combination of a relatively high carrier frequency (1/26,222, second after p.Arg98*) and its occurrence in populations characterized by a higher degree of consanguinity. The gene discussed is TNNI3; the disease is familial dilated cardiomyopathy.