Som regel kendetegnes den ved tilstedeværelsen af tilstrækkelig resterende GAA- aktivitet, hvilket forhindrer udviklingen af kardiomyopati, men nogen involvering af hjertet er rapporteret hos op til ca.
Usually, it is characterised by the presence of sufficient residual GAA activity to preclude the development of cardiomyopathy, however some cardiac involvement has been reported in up to approximately 4% of patients with late-onset Pompe disease.