Muscle Weakness (Myopathy)


The body is full of muscles, and each one must do its part for maximum mobility and health. When muscle fibers are mutated, they can’t do their jobs properly, and muscle weakness, also known as myopathy, occurs. Congenital myopathy (myopathy present at birth or infancy) can cause developmental delays and other problems. Over time, congenital myopathy can weaken a child such that he or she struggles with an array of basic activities, including breathing. However, many with congenital myopathy live long and healthy lives.


  • Central core disease impacts the skeletal muscles, and most people with central core disease have consistent, mild muscle weakness.
  • Centronuclear myopathy causes wasting and muscle weakness in the skeletal muscles.
  • Congenital fiber-type disproportion myopathy, which is caused by specific genetic mutations, leads to breathing issues, facial weakness, floppiness and limb weakness.
  • Hyaline body myopathy causes slowly progressive muscle weakness and increasing muscle pain • Multiminicore disease can cause scoliosis (curvature of the spine), as well as severe muscle weakness in the extremities.
  • Myotubular myopathy, which mostcommonly develops in males, can result in breathing issues, diminished muscle tone and general muscle weakness.
  • Nemaline myopathy can cause breathing problems, feeding difficulties, scoliosis, and arm, facial, leg and neck muscle weakness.


  • A floppy appearance of the limbs
  • Difficulty eating or breathing
  • Difficulty meeting developmental milestones that require muscle function
  • Muscle stiffness, cramps or spasms
  • Weak bones, limbs or facial muscles
  • Weakened eye movements


Currently, there is no known way to prevent congenital myopathy.

Risk Factors

Family history of myopathy


  • Medical history and symptom review. The child’s personal and family medical history are reviewed, along with symptoms. 
  • Physical examination. The doctor performs various tests to determine the child’s strength and reflexes. 
  • Genetic testing. Because genetics are often at play in myopathies, DNA tests may help determine whether a myopathy or other condition is present.
  • Biopsy. A small sample of the child’s muscle is removed and studied under a microscope.


  • Medication may help children with central core disease. This is the only myopathy with a specific treatment option. •
  • Medication, therapy and even surgery may be called upon to relieve specific symptoms and subsequent side effects of the myopathy.

Follow-up Care

  • Because scoliosis often develops in children with myopathy, regular scoliosis testing is recommended.
  • Working with a multidisciplinary team is recommended to keep a close eye on every aspect of a child’s health and well-being when living with myopathy.