Below is an instruction from Human. Write a response.
    ### Instruction:
    What are the genetic changes related to cap myopathy ?
    ### Response:
    Mutations in the ACTA1, TPM2, or TPM3 genes can cause cap myopathy. These genes provide instructions for producing proteins that play important roles in skeletal muscles.  The ACTA1 gene provides instructions for making a protein called skeletal alpha ()-actin, which is part of the actin protein family.
    