What is congenital fiber-type disproportion?
Congenital fiber-type disproportion is a disorder that primarily affects skeletal muscles, which are muscles the body uses for movement. People with this disorder typically experience muscle weakness (myopathy) throughout the body, particularly in the muscles of the shoulders, upper arms, hips, and thighs. Weakness can also affect the muscles of the face and muscles that control eye movement (ophthalmoplegia), sometimes causing droopy eyelids (ptosis). Affected people may have joint deformities (contractures) and an abnormally curved lower back (lordosis) or a spine that curves to the side (scoliosis). Approximately 30 percent of people with this disorder experience mild to severe breathing problems related to weakness of muscles needed for breathing. Some people who experience these breathing problems require extra support and use a detachable mask (noninvasive mechanical ventilation) to help them breathe at night, and occasionally during the day as well. About 30 percent of affected
