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NINDS Spinal Muscular Atrophy Information Page

Synonym(s):   Werdnig-Hoffman Disease, Kugelberg-Welander Disease
Condensed from Spinal Muscular Atrophy Fact Sheet

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What is Spinal Muscular Atrophy?

Spinal Muscular Atrophy (SMA) Types I, II, and III belong to a group of hereditary diseases that cause weakness and wasting of the voluntary muscles in the arms and legs of infants and children. The disorders are caused by an abnormal or missing gene known as the survival motor neuron gene 1 (SMN1), which is responsible for the production of a protein essential to motor neurons. Without this protein, lower motor neurons in the spinal cord degenerate and die. The type of SMA (I, II, or III) is determined by the age of onset and the severity of symptoms. Type I (also known as Werdnig-Hoffman disease, or infantile-onset SMA) is evident at birth or within the first few months. Symptoms include floppy limbs and trunk, feeble movements of the arms and legs, swallowing and feeding difficulties, and impaired breathing. Type II (the intermediate form) usually begins 6 and 18 months of age. Legs tend to be more impaired than arms. Children with Type II may able to sit and some may be able to stand or walk with help. Symptoms of Type III (also called Kugelberg-Welander disease) appear between 2 and 17 years of age and include difficulty running, climbing steps, or rising from a chair.  The lower extremities are most often affected.  Complications include scoliosis and chronic shortening of muscles or tendons around joints.  

Is there any treatment?

There is no cure for SMA. Treatment consists of managing the symptoms and preventing complications.

What is the prognosis?

The prognosis is poor for babies with SMA Type I. Most die within the first two years. For children with SMA Type II, the prognosis for life expectancy or for independent standing or walking roughly correlates with how old they are when they first begin to experience symptoms - older children tend to have less severe symptoms  Life expectancy is reduced but some individuals live into adolescence or young adulthood.  Individuals with SMA type III may be prone to respiratory infections but with care may have a normal lifespan.

What research is being done?

Between 2003 and 2012, the NINDS piloted the Spinal Muscular Atrophy Project to expedite therapeutics development for this hereditary neurodegenerative disease. The Project was designed to accelerate the research process by identifying drugs that increase the level of SMN protein in cultured cells, so that they could be used as potential leads for further drug discovery and clinical testing. Read more about the history of this pioneering effort and how it led to collaboration with several pharmaceutical and biotechnology companies. (LINK TO SUMMARY)

NIH Patient Recruitment for Spinal Muscular Atrophy Clinical Trials

Organizations

Column1 Column2
Fight SMA
1321 Duke Street
Suite 304
Alexandria, VA   22134
web@fightsma.org
http://www.fightsma.org
Tel: 703-299-1144

Families of Spinal Muscular Atrophy
925 Busse Road
Elk Grove Village, IL   60007
info@fsma.org
http://www.curesma.org
Tel: 800-886-1762
Fax: 847-367-7623

Spinal Muscular Atrophy Foundation
888 Seventh Avenue
Suite 400
New York, NY   10019
info@smafoundation.org
http://www.smafoundation.org
Tel: 877-FUND-SMA (877-386-3762) 646-253-7100
Fax: 212-247-3079

Muscular Dystrophy Association
3300 East Sunrise Drive
Tucson, AZ   85718-3208
mda@mdausa.org
http://www.mda.org
Tel: 520-529-2000 800-572-1717
Fax: 520-529-5300

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Prepared by:
Office of Communications and Public Liaison
National Institute of Neurological Disorders and Stroke
National Institutes of Health
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Last updated April 16, 2014