Spinal Muscular Atrophy (SMA) is a diseased distinguished by loss of motor function or muscle atrophy because of the absence of SMN1 gene or the Survival Motor Neuron 1. This SMN1 gene predetermines survival of the SMN protein which is very important to the survival of the nerve cells of the spinal cord which is accountable for the muscle contraction. If these nerve cells are unhealthy because of low levels of SMN then it may result to Spinal Muscular Atrophy.
Spinal muscular atrophies consist of groups of autosomal recessive disorders which are distinguished by advancing weakness of the lower motor neurons. There are several types of SMA and is distinguished by age. The most common type of SMA is Type 1 which is known as Werding-Hoffman Disease (acute infantile), the type II is the chronic infantile, Type III is the Kugelberg-Welander disease (chronic juvenile) and the Type IV which s the adult onset (J Child Neurol. 2007).
SMA is the second common inherited disease after cystic fibrosis in the United States. Type I of SMA alone affects one in every ten thousand live births while the chronic forms of SMA which are the type II and III affect one every twenty-four thousand births. Types I and III comprise about one fourth of cases while the Type II account for the largest group which is one half of all cases. Internationally, a case of SMA is about one in every ten thousand live births with carrier frequency of one in fifty.
Spinal muscular athrophy type 2 or II is the most numbered cases of spinal muscular athrophy. Children with type 2 spinal muscular athrophy suffers less severe weakness than children with type 1.
Symptoms of Spinal Muscular Atrophy
Due to the loss of neurons in the spinal cord, progressive loss of muscle control, movement as well as increasing weakness occurs. The ones most severely affected are the muscles that are closest to the center of the body like the ones in the neck and trunk. Severity of SMA depends on what type of SMA you have and of course the age of onset although most patients with this condition often shows symptoms early and that is during infancy stage or toddler stage. With SMA type 2 symptoms is observed later in life mostly in age six to eighteen months.Children with type 2 can usually sit on their own yet they do not have the ability to stand without support or walk in their own.
Individuals who have this condition often have spinal deformities which may need surgical treatment. A person who suffers from this condition is also prone to respiratory illnesses which may even turn severe. It is important then that parents who have children that have SMA should take extra care of their kids to have the right nutritional support, respiratory therapy, occupational and physical therapy for them to enjoy a quality life.
Spinal Muscular Atrophy Life Expectancy
SMA is a genetic disorder which is distinguished by advance muscle weakening and loss. Since the muscle that is controlling breathing is severely affected by this disease, this can lead to premature death. Life expectancy of individual who have SMA depends on what SMA type the individual have. Children who are identified to have SMA type I may live up to two years or even longer which depends mostly in their strength. Children who has mild form of SMA like having SMA type II and III mostly survive till their adulthood and can even have a normal life expectancy as long as the individual observes a good multidisciplinary care which includes having a good nutritional support, occupational therapy, respiratory therapy and of course physical therapy. This individual will certainly enjoy a good quality life.