MYH14 and congenital myopathy with cores: It should be noted that for most of the myopathies studied (regardless of whether they have high or low Ca2+-sensitivity), an increase in the number of myosin heads in AM and/or AM^•ADP states was found at relaxation (Table 1), and this is one of the primary causes for disorganization of the contractile apparatus at congenital myopathies.