Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) X-linked myotubular myopathy ?
    ### Response:
    X-linked myotubular myopathy is a condition that primarily affects muscles used for movement (skeletal muscles) and occurs almost exclusively in males. People with this condition have muscle weakness (myopathy) and decreased muscle tone (hypotonia) that are usually evident at birth.
    