Spinal Muscular Atrophy is, as the name suggests, a disease involving the spinal cord, more specifically the anterior horn cells located within the spinal cord
. It is classified as a neuromuscular
disorder. This condition varies drastically in severity and can be anywhere from completely debilitating to manageable with no real detriment to the inflicted individuals life. The disorder was first discovered in adults around 1850, later another type was discovered in children. Eventually, they established the five types listed above.
The initial diagnosis of SMA often leads to more intensive testing to determine exactly which of the five types is concerned in each case. These tests may include blood
(to test for high levels of CPK
), measuring the electrical activity of muscle
, and sometimes muscle biopsy
. More recently there have been improvements in diagnosis methods and much simpler gene testing may help to determine if the disease is present with less discomfort to the patient.
Typically, those affected will experience weakness in regards to voluntary muscle
movement, especially in the legs which are nearest the anterior horn cells
themselves. Weakness in the arms is not uncommon but is often less severe. Breathing can also be affected as the muscles involved in the respiration
process are often weakened as well. In chronic cases lifting of the head and swallowing may be compromised, sometimes a feeding tube
is necessary. Facial muscles are not usually affected, as most of the symptoms involve the body itself, especially the trunk. The worst cases of SMA are fatal, and life prior to death is generally complicated and unpleasant. It is important to note that this disease does not hinder intelligence
, many of those inflicted have above average intelligence levels.
This is a genetic disorder
and is passed on by the parents of those infected. Both parents must carry the disease in order for it to pass on to the child, the frequency rate for children affected when both parents carry the gene is 25%. Adult SMA is slightly different and may be caused by a recessive gene
passed on through family generations. This disease effects one in every 40 people who carry the gene necessary and one in every 6,000 babies is born with SMA.
There are many support groups for families and those who are living with SMA. It is one of the most common genetic disorders in the world.
sources: http://www.fsma.org/sma_facts.htm, http://www.mdausa.org/publications/fa-sma.html.