Muscular dystrophy (MD) refers to a group of more than 30 genetic diseases characterized by progressive weakness and degeneration of the skeletal muscles that control movement. Some forms of MD are seen in newborns, infants or children, while others have late-onset and may not appear until middle age or later. The disorders differ in terms of the distribution and extent of muscle weakness (some forms of MD also affect cardiac muscle), age of onset, rate of progression, and pattern of inheritance. The prognosis for people with MD varies according to the type and progression of the disorder. There is no specific treatment to stop or reverse any form of MD. Treatment is supportive and may include physical therapy, respiratory therapy, speech therapy, orthopedic appliances used for support, corrective orthopedic surgery, and medications including corticosteroids, anticonvulsants (seizure medications), immunosuppressants, and antibiotics. Some individuals may need assisted ventilation to treat respiratory muscle weakness or a pacemaker for cardiac (heart) abnormalities.
Last updated: 2/16/2011
What conditions are part of the differential diagnosis for Duchenne muscular dystrophy?
Duchenne muscular dystrophy (DMD) is a type of dystrophinopathy, which is a group of muscle diseases caused by mutations in the DMDgene, which encodes the protein dystrophin; the other dystrophinopathies are Becker muscular dystrophy (BMD) and DMD-associated dilated cardiomyopathy (DCM). Although these disorders are caused by mutations in the same gene, they do differ with regard to age of onset, course and pace of progression, symptoms, and life expectancy. DMD and BMD primarily affect the skeletal muscles, while DCM primarily affects the heart.
Conditions that may be part of the differential diagnosis of the dystrophinopathies include:
Limb-girdle muscular dystrophy (LGMD): a group of disorders that are similar to DMD but occur in both sexes as a result of autosomal recessive and autosomal dominant inheritance. LGMD type 2I has symptoms that resemble DMD and/or BMD and is caused by mutations in the FKRP gene.
Emery-Dreifuss muscular dystrophy (EDMD): characterized by joint contractures that begin in early childhood, slowly progressive muscle weakness and wasting that follows a specific distribution pattern over time, and cardiac (heart) involvement that may include palpitations, presyncope (feeling of faintness) and syncope (fainting), poor exercise tolerance, and congestive heart failure. Age of onset, severity, and progression of the muscle and cardiac involvement are variable. The two genes known to be associated with EDMD are EMD (X-linked EDMD) and LMNA (autosomal dominant EDMD and autosomal recessive EDMD).
Spinal muscular atrophy (SMA): suspected in individuals with poor muscle tone, symmetric muscle weakness that does not affect the face and ocular (eye) muscles, and evidence of anterior horn cell involvement (a motor neuron in the spinal cord), including muscle twitches of the tongue and absence of deep tendon reflexes. SMA is caused by mutations in the SMN1 gene. Inheritance is autosomal recessive.
Dilated cardiomyopathy (DCM): can be familial or non-familial. Familial DCM can have autosomal dominant, autosomal recessive, or X-linked inheritance.
Last updated: 5/31/2011
Can Russell-Silver syndrome mimic muscular dystrophy?
Russell-Silver syndrome and muscular dystrophy are very different types of disorders with little overlap of signs and symptoms; Russell-Silver syndrome does not mimic muscular dystrophy. Russell-Silver syndrome is a growth disorder and is characterized by slow growth before and after birth, poor appetite, short stature, a small, triangular face with distinctive facial features, and other manifestations; the muscular dystrophies are a group of muscle disorders characterized by progressive weakness and degeneration of the skeletal muscles and/or cardiac muscles. The differential diagnosis of Russell-Silver syndrome includes any condition that can cause intrauterine growth retardation and short stature, as well as some chromosome abnormalities, while that of the muscular dystrophies includes conditions affecting the skeletal muscles.
Last updated: 11/30/2011
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