A similar switch is observed in the expression of titin isoforms: embryonic hearts express much higher levels of the N2BA isoform of titin, which is replaced by the shorter N2B titin isoform in the perinatal and adult heart [31]; therefore, expression of the long-form N2BA in the adult heart is used as a marker of pathological cardiac hypertrophy. This evidence concerns the gene TTN and cardiac hypertrophy.