Werdnig-Hoffmann Disease
National Organization for Rare Disorders, Inc.
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General Discussion
The spinal muscular atrophies (SMAs), are characterized by degeneration of nerve cells (motor nuclei) within the lowest region of the brain (lower brainstem) and certain motor neurons in the spinal cord (anterior horn cells) leading to muscle weakness of the truncal, and extremity muscles initially, followed by chewing, swallowing and breathing difficulties. Motor neurons are nerve cells that transmit nerve impulses from the spinal cord or brain (central nervous system) to muscle or glandular tissue.
Approximately 80 percent of individuals with SMA fall into the severe category (Werdnig-Hoffmann disease or SMA1). Infants with SMA1 experience severe weakness before 6 months of age, and the patient never achieves the ability to sit independently when placed. Muscle weakness, lack of motor development and poor muscle tone are the major clinical manifestations of SMA1. Infants with the gravest prognosis have problems sucking or swallowing. Some show abdominal breathing in the first few months of life. Abdominal breathing is noted when the abdomen protrudes during inspiration. Normally, the chest expands during inspiration as the intercostal muscles (the muscles between the ribs) expand during inspiration. Abdominal breathing occurs when the intercostal muscles are weak and the diaphragm muscle is responsible for inspiration. Movement of the diaphragm (the muscle between the chest and abdomen) expands causing the abdomen to move during the inspiration cycle. Twitching of the tongue is often seen (fasciculations). Cognitive development is normal. Most affected children die before 2 years of age but survival may be dependent on the degree of respiratory function and respiratory support.
The different subtypes, SMA 0-4 are based on the age of onset of symptoms and the course and progression of the disease. SMA represents a continuum or spectrum of disease with a mild end and a severe end. SMA0 patients are extremely weak at birth, require immediate artificial ventilation and will never breathe independently. Werdnig-Hoffmann disease, which is also known as spinal muscular atrophy type 1 (SMA1) or acute spinal muscular atrophy, refers to individuals who have symptom onset prior to 6 months of age. SMA 2 patients will show symptoms prior to age 1 year, will sit but never walk. SMA 3 patients (Kugelberg-Welander disease) will show symptoms after age 1, and will walk for a period of time prior to loss of motor abilities. SMA 4 patients will not develop symptoms much before age 10 years.
All the SMAs are inherited as an autosomal recessive trait. Molecular genetic testing has revealed that all types of autosomal recessive SMA are caused by disruptions or errors (mutations) in the SMN1 (survival motor neuron 1) gene on chromosome 5.
Supporting Organizations
Child Neurology Foundation
- 201 Chicago Ave, #200
- Minneapolis, MN 55415
- USA
- Tel: (952)641-6100
- Fax: (952)881-6276
- Tel: (877)263-5430
- Email: jstone@childneurologyfoundation.org
- Website: http://www.childneurologyfoundation.org
Children with Spinal Muscular Atrophy, Ukraine - Kharkiv Charitable Foundation
- Gogolia Street 7
- Kharkiv, 61057
- Ukraine
- Tel: 380503640673
- Email: info@csma.org.ua
- Website: http://www.csma.org.ua
Claire Altman Heine Foundation, Inc.
- 1112 Montana Avenue, #372
- Santa Monica, CA 90403
- Tel: (310)260-3262
- Fax: (310)393-7154
- Email: deb@preventsma.org
- Website: http://www.clairealtmanheinefoundation.org
Cure SMA
- 925 Busse Road
- Elk Grove Village, IL 60007
- Tel: (847)367-7620
- Tel: (800)886-1762
- Email: info@cureSMA.org
- Website: http://www.cureSMA.org/
Fight SMA/Spinal Muscular Atrophy
- 1321 Duke Street
- Suite 104
- Alexandria, VA 22314
- Tel: (703)299-1144
- Email: CarolineGibson@fightsma.com
- Website: http://www.fightsma.org
Genetic and Rare Diseases (GARD) Information Center
- PO Box 8126
- Gaithersburg, MD 20898-8126
- Tel: (301)251-4925
- Fax: (301)251-4911
- Tel: (888)205-2311
- Website: http://rarediseases.info.nih.gov/GARD/
Jennifer Trust for Spinal Muscular Atrophy
- 40 Cygnet Court
- Timothy's Bridge Road
- Warwickshire, CV37 9NW
- United Kingdom
- Tel: 4401789267520
- Fax: 4401789268371
- Tel: 8009753100
- Email: office@jtsma.org.uk
- Website: http://www.jtsma.org.uk
March of Dimes
- 1275 Mamaroneck Avenue
- White Plains, NY 10605
- Tel: (914)997-4488
- Fax: (914)997-4763
- Email: AskUs@marchofdimes.org or preguntas@nacersano.org
- Website: http://www.marchofdimes.org and nacersano.org
Muscular Dystrophy Association
- 3300 East Sunrise Drive
- Tucson, AZ 85718-3208
- USA
- Tel: (520)529-2000
- Fax: (520)529-5300
- Tel: (800)572-1717
- Email: mda@mdausa.org
- Website: http://www.mda.org/
Muscular Dystrophy Campaign
- 61 Southwark Street
- London, SE1 0HL
- United Kingdom
- Tel: 2078034800
- Email: info@muscular-dystrophy.org
- Website: http://www.muscular-dystrophy.org
NIH/National Institute of Neurological Disorders and Stroke
- P.O. Box 5801
- Bethesda, MD 20824
- Tel: (301)496-5751
- Fax: (301)402-2186
- Tel: (800)352-9424
- Website: http://www.ninds.nih.gov/
For a Complete Report
This is an abstract of a report from the National Organization for Rare Disorders (NORD). For a full-text version of this report, go to www.rarediseases.org and click on Rare Disease Database under "Rare Disease Information".
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This disease entry is based upon medical information available through the date at the end of the topic. Since NORD's resources are limited, it is not possible to keep every entry in the Rare Disease Database completely current and accurate. Please check with the agencies listed in the Resources section for the most current information about this disorder.
Last Updated: 3/26/2012
Copyright 2012 National Organization for Rare Disorders, Inc.
