National Organization for Rare Disorders, Inc.
It is possible that the main title of the report Werdnig-Hoffmann Disease is not the name you expected. Please check the synonyms listing to find the alternate name(s) and disorder subdivision(s) covered by this report.
- SMA 1
- infantile spinal muscular atrophy
- SMA, infantile acute form
- spinal muscular atrophy type 1
- Werdnig-Hoffman paralysis
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.
March of Dimes Birth Defects Foundation
1275 Mamaroneck Avenue
White Plains, NY 10605
925 Busse Road
Elk Grove Village, IL 60007
Muscular Dystrophy Association
3300 East Sunrise Drive
Tucson, AZ 85718-3208
Muscular Dystrophy Campaign
61 Southwark Street
London, SE1 0HL
NIH/National Institute of Neurological Disorders and Stroke
P.O. Box 5801
Bethesda, MD 20824
Jennifer Trust for Spinal Muscular Atrophy
40 Cygnet Court
Timothy's Bridge Road
Stratford upon Avon
Warwickshire, CV37 9NW
Genetic and Rare Diseases (GARD) Information Center
PO Box 8126
Gaithersburg, MD 20898-8126
PO Box 241956
Los Angeles, CA 90024
Fight SMA/Spinal Muscular Atrophy
1321 Duke Street
Alexandria, VA 22314
Claire Altman Heine Foundation, Inc.
1112 Montana Avenue, #372
Santa Monica, CA 90403
Children with Spinal Muscular Atrophy Ukraine
Gogolia Street 7
Child Neurology Foundation
201 Chicago Ave, #200
Minneapolis, MN 55415
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Last Updated: 3/26/2012
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