A muscle wasting disorder mainly involving the muscles in the arms, legs, face, neck, spine and heart. Symptoms generally only occur in males but female carriers may have some symptoms
* Muscle weakness * Walking on tip-toes * Waddling gait * Weakness of shoulder girdle muscles * Lumbar lordosis
Muscular dystrophy is caused by various genetic mechanisms. Duchenne’s and Becker’s muscular dystrophies are X-linked recessive disorders. Both result from defects in the gene coding for the muscle protein dystrophin; the gene has been mapped to the Xp21 locus. The incidence muscular dystrophy is about 1 in 651,450 persons in the United States. Duchenne’s and Becker’s muscular dystrophies affect males almost exclusively. Facioscapulohumeral dystrophy is an autosomal dominant disorder. Limb-girdle dystrophy is usually autosomal recessive. These two types affect both sexes about equally.