TNNT1 and familial hypertrophic cardiomyopathy: This exon encodes 4–5 amino acids and its alternative splicing results in relatively small change of N-terminal charge of cardiac TnT. Alternative splicing is normally found in rabbit, rat, mouse, and bovine hearts (Biesiadecki and Jin, 2002) and is increased in human heart failure (Anderson et al., 1991, 1995), human familial hypertrophic cardiomyopathy (Thierfelder et al., 1994), and the heart of diabetic rats (Akella et al., 1995).