In monogenic cardiomyopathies caused by LoF variants in the giant muscle protein titin, studies of TTN expression levels indicate that LoF variants found in unaffected population cohorts occur predominantly in exons that are absent from the most highly expressed transcripts and thus do not cause the phenotypic effect associated with deleterious variants (Begay et al., 2015; Akinrinade et al., 2019). The gene discussed is TTN; the disease is cardiomyopathy.