GETTING TO KNOW SMA:
VARIOUS DEFINITIONS
DEFINITIONS FOUND OVER THE INTERNET
Families of Spinal Muscular Atrophy: FSMA
National Organization for Rare Diseases NORD
National Institute of Neurological Disorders NINDS
National Institute of Health: Office of Rare Disease Research GARD
University of Utah, SMA focus Department of Pediatric Neurology
DEFINITION
What follows is a segment of the definition of SMA can be found at the link I mentioned above on FSMA. To see all the detailed information, visit this page (written in Spanish). Here we only include definition of SMA and SMA Type 1, as Deirdre is Type 1.
What is Spinal Muscular Atrophy?
Spinal Muscular Atrophy (SMA) is a disease of motor neurons. The motor neurons affect the voluntary muscles that are used for activities such as crawling, walking, controlling the neck and head, and swallowing. This is a "rare disorder" relatively common: about 1 in every 6000 babies are affected and 1 in 40 people is a genetic carrier.
SMA affects muscles throughout the body, although the proximal muscles (those closest to the trunk, such as shoulders, hips and back) are usually more severely affected. The weakness in the legs is generally greater than in the arms. Sometimes feeding and swallowing can be affected. The muscles involved in breathing (the muscles on breathing and coughing) can lead to an increased tendency to suffer from pneumonia or other lung problems. The sensitivity and the ability to feel are not affected. Intellectual activity is normal and is often observed that patients with SMA are unusually bright and sociable. Patients are generally grouped into four categories based on key indicators of motor functions accurate.
What causes Spinal Muscular Atrophy?
SMA is an autosomal recessive genetic disease. For a child to be affected by SMA, both parents must carry the abnormal gene and both must pass this gene to his son. Although both parents carry the probability that a (a) child (a) inherit the disorder is 25% or 1 in 4.
An individual with SMA has a missing or mutated gene (SMN1, survival motor neuron 1 or - surviving motor neuron 1) that produces a protein in the body called Motor Neuron NMS Surviving (Survival Motor Neuron - SMN). A deficiency of this protein has a more severe condition in motor neurons. Motor neurons are nerve cells called the spinal cord, which send nerve fibers to muscles throughout the body. Since SMN protein is critical to health and survival of motor neurons, without this protein nerve cells may atrophy, shrink and eventually die, resulting in muscular weakness.
Between a child with SMA grows their bodies are doubly tense, first by the decrease in motor neurons and then by increased demand in nerve cells and muscle in your body as it grows. The resulting muscle atrophy can cause weakness and bone and spinal deformities that may incur the loss of other functions as well as additional commitments in the respiratory system.
There are four types of SMA, SMA type I, II, III, IV. Determining the type of SMA is based on physical indicators achieved. It is important to note that the course of the disease may be different from one infant to another.
Type I
SMA type I, also called Werdnig-Hoffman syndrome. The diagnosis of children with this type is usually done earlier than 6 months old and in most cases are diagnosed before 3 months. Some mothers even notice the downward movement of the fetus in late pregnancy.
Usually, a child with Type I is never able to lift his head or motor goals expected in early childhood. They generally have little control of the head and may not kick the legs vigorously as they are supposed to or bear weight on his legs. They hit us the ability to sit without support. Chewing and swallowing can be difficult and usually are affected at some point, and the child may show difficulties in controlling their own secretions. The tongue may show atrophy and a fine undulating movements or tremors, also called fasciculations. There is weakness of the intercostal muscles (the muscles between the ribs) that help expand the chest and the chest is often smaller than usual. The strongest respiratory muscle in a patient with SMA is the diaphragm. As a result, the patient seems to breathe with the muscles of his stomach. The chest may appear concave (sunken) due to diaphragmatic breathing (stomach). Also, because this type of breathing, the lungs may not fully develop, the cough is very weak, and can be difficult to take deep breaths while sleeping to maintain normal levels of oxygen and carbon dioxide.
Visit FSMA for details of other types of SMA, how it is diagnosed, the prognosis (what to expect) and what to do if you're carrying the gene for SMA.
OTHER SMA ORGANIZATIONS
CLAIRE ALTMAN HEINE FOUNDATION
EVERYTHING ABOUT SPINAL MUSCULAR ATROPHY
IMPORTANT BASIC DOCUMENTS THAT EVERYONE MUST HAVE
SMA Consensus of Standards of Care 2007
LET'S DESTROY THIS MONSTER!
DAILY CARE MANUAL FOR DEIRDRE MEDINA
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