3 Prenatal or pre-implantation diagnosis is possible. Unless the usual X-inactivation process is highly skewed toward the X with the abnormal gene, female carriers typically have minimal if any weakness but are at risk for cardiac effects. Sons have a 50% chance of being affected, and daughters a 50% chance of being a carrier. The only known risk factor is being born to a female carrier.

There is remarkably little variation with ethnicity. Epidemiology including risk factors and primary preventionĪpproximately 1 in 3,500 live male births are affected by DMD, and about 1 in 20,000 have BMD. Duplications, nonsense and missense base pair substitutions, and intronic changes may also cause disease. Sixty to seventy percent of mutations are deletions of one or more exons. About 1/3 of cases result from de novo mutations in the gene. 1,2 EtiologyĭMD and BMD are X-linked recessive. DMD is the more common and severe form with non-functional dystrophin protein molecules, and BMD is typically a milder phenotype with abnormal but partially functional dystrophin. They are defined by muscle degeneration, regeneration, and fibrosis. Torticollis in Children and Adolescentsĭuchenne Muscular Dystrophy (DMD) and Becker Muscular Dystrophy (BMD), also referred to as the dystrophinopathies, are forms of progressive muscular dystrophy associated with defects in the dystrophin gene, located at Xp21.2-21.1.Peripheral Polyneuropathy Part 1: Evaluation and Differential Diagnosis.Peripheral Polyneuropathy Part 2: Treatment.AIDP/CIDP Part 1: Evaluation and Diagnosis.Pediatric Immune Mediated Brachial Plexopathy.Hereditary Motor Sensory Neuropathy (HMSN).Adult and Adolescent Onset Muscular Dystrophies Part 1: Evaluation and Diagnosis.Nondystrophic myotonia and periodic paralysis.Adult and Adolescent Muscular Dystrophies Part 2: Rehabilitation Management and Treatments.

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