G08: Science Genetic Disorders: Muscular Dystrophy

Duchenne muscular dystrophy (DMD) is a rare muscle disorder but it is one of the most frequent genetic conditions affecting approximately 1 in 3,500 male births worldwide. It is usually recognized between three and six years of age. DMD is characterized by weakness and wasting (atrophy) of the muscles of the pelvic area followed by the involvement of the shoulder muscles.

Muscular dystrophy is a group of diseases that cause progressive weakness and loss of muscle mass. In muscular dystrophy, abnormal genes (mutations) interfere with the production of proteins needed to form healthy muscle.

There are many kinds of muscular dystrophy. Symptoms of the most common variety begin in childhood, mostly in boys. Other types don't surface until adulthood.

Congenital muscular dystrophy (CMD) is a general term for a group of genetic muscle diseases that occur at birth (congenital) or early during infancy. CMDs are generally characterized by diminished muscle tone (hypotonia), which is sometimes referred to as “floppy baby”; progressive muscle weakness and degeneration (atrophy); abnormally fixed joints that occur when thickening and shortening of tissue such as muscle fibers cause deformity and restrict the movement of an affected area (contractures); spinal rigidity, and delays in reaching motor milestones such as sitting or standing unassisted. Feeding difficulties and breathing (respiratory) complications can develop in some cases.

Discover more about muscular dystrophies and other muscle wasting and weakening conditions. For detailed information on symptoms, causes, diagnosis, and treatment of over 60 related conditions, visit our Conditions A-Z page.