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Congenital Muscular Dystrophy

Congenital muscular dystrophy (Congenital MD) refers to a group of autosomal recessive muscular dystrophies that are either present at birth or become evident before age 2. They affect both boys and girls. The degree and progression of muscle weakness and degeneration vary with the type of disorder. Weakness may be first noted when children fail to meet landmarks in motor function and muscle control. Muscle degeneration may be mild or severe and is restricted primarily to skeletal muscle. The majority of patients are unable to sit or stand without support, and some affected children may never learn to walk. There are three groups of congenital MD:

  • merosin-negative disorders, where the protein merosin (found in the connective tissue that surrounds muscle fibers) is missing;
  • merosin-positive disorders, in which merosin is present but other needed proteins are missing; and
  • neuronal migration disorders, in which very early in the development of the fetal nervous system the migration of nerve cells (neurons) to their proper location is disrupted.

Defects in the protein merosin cause nearly half of all cases of congenital MD.

Patients with congenital MD may develop contractures (chronic shortening of muscles or tendons around joints, which prevents the joints from moving freely), scoliosis, respiratory and swallowing difficulties, and foot deformities. Some patients have normal intellectual development while others become severely impaired. Weakness in diaphragm muscles may lead to respiratory failure. Congenital MD may also affect the central nervous system, causing vision and speech problems, seizures, and structural changes in the brain. Some children with the disorders die in infancy while others may live into adulthood with only minimal disability.

 

Reference:

National Institute of Neurological Disorders and Stroke, USA.