Hence, in the present study, we hypothesized that, in RYR1‐related congenital myopathies, unusual PTMs in particular acetylation and phosphorylation would appear on myosin molecules, more specifically on its myosin heavy chains (MyHCs) rich in lysine, serine, tyrosine, and threonine residues. This evidence concerns the gene MYH14 and congenital myopathy with cores.