Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) TK2-related mitochondrial DNA depletion syndrome, myopathic form ?
    ### Response:
    TK2-related mitochondrial DNA depletion syndrome, myopathic form (TK2-MDS) is an inherited condition that causes progressive muscle weakness (myopathy).  The signs and symptoms of TK2-MDS typically begin in early childhood. Development is usually normal early in life, but as muscle weakness progresses, people with TK2-MDS lose motor skills such as standing, walking, eating, and talking.
    