Symptoms of FCMD

Fukuyama congenital muscular dystrophy (FCMD), a rare type of MD seen almost exclusively in the Japanese population, usually is marked by progressive weakness in skeletal muscles and problems in brain development.

Known as FCMD, this rare muscular dystrophy is an inherited condition caused by a mutation in the FKTN gene. That gene carries the instruction to make a protein called fukutin.

The exact function of fukutin protein is unclear, but there is some evidence suggesting that it may play a role in the modification of another protein called alpha-dystroglycan. The alpha-dystroglycan protein stabilizes the skeletal muscles and supports the movement of nerve cells in the brain during early development.

In FCMD, the defective fukutin protein may result in improperly-working alpha-dystroglycan, which may lead to the disease’s muscular and developmental symptoms.

FCMD and the skeletal muscles

Skeletal muscles are those muscles that support movement. The initial symptoms of skeletal muscle weakness due to FCMD appear in early infancy — infants appear floppy. Other skeletal muscles related symptoms include:

  • Poor feeding
  • Weak cry
  • Droopy eyelids due to weak facial muscles
  • Joint deformities or contractures that affect movement
  • Progressive muscle weakness leading to poor development of motor skills, including sitting, standing, and walking

FCMD and the brain

Brain development also is affected in patients with FCMD. The characteristic manifestation is the development of cobblestone lissencephaly or a bumpy, irregular brain surface that resembles cobblestones. This structural deformity of the brain impedes speech development, causes moderate-to-severe intellectual disability, and leads to poor social skills. Seizures also are common in people with FCMD.

Other symptoms

As the condition progresses, other muscles in the body also may be affected. This can cause several other symptoms:

  • Weakness of the eye muscles can lead to impaired vision and other eye problems.
  • The heart muscle may be affected, and patients may develop cardiomyopathy — a disease of the heart muscle that makes it harder for the heart to pump blood to the rest of the body — and heart failure.
  • Weakness in the facial muscles may cause progressive difficulty in swallowing.
  • Patients may often develop lung infections, like pneumonia, as the muscles used for breathing progressively weaken.


Last updates: August 20, 2019


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