People who inherit a faulty SOD1 gene have a high, but as yet uncertain, chance of developing MND in later life. However, some people with a mutation in their SOD1 gene will not develop MND during their lifetime.
Some people who appear to have sporadic MND also have mutations in the SOD1 gene. The proportion is not known.
Mutations in other unidentified genes can cause familial MND.
How Motor Neurone Disease is inherited:
Only a small number of diagnoses are inherited through a family history of the disease, about 10% of disease cases are inherited, caused by at least 100 different mutations in a protein known as SOD1. If a person has MND as a result of a mutation in SOD1, each of their children has a 50/50 chance of inheriting the faulty gene.
Signs and Symptoms:
Motor Neurone Disease affects individuals in different ways, when the upper body is affected; clumsy fingers and a weak grip are evident. After a while, simple tasks like turning door handles may become difficult. When the lower body is affected, raising the feet with each step can be difficult, causing them to drag on the ground. After a gradual onset, muscle control is lost in these areas and the disease affects more and more areas of the body. Sufferers will eventually have to use wheelchairs to move around. Constipation can occur because of this restricted movement. Sometimes it’s the throat muscles that are mainly involved, and this may lead to difficulties in swallowing and speech. There is also a development of breathing problems involved as the disease progresses to affect the chest. Muscular twitches, pain and stiffness can develop around the joints where he muscles are affected. Mentally there aren’t usually changes, but some people with the disease experience a change in personality or some degree of intellectual difficulty.
Prevalence:
Approximately 1-5 people of each 100,000 are diagnosed with the disease. It’s primarily evidenced by people between 50 and 70 years of age, and more commonly in men than women.
Treatment:
Riluzole is a drug that reduces the progression of the disease by several months; it is the only direct treatment for Motor Neurone Disease available. There are of course other drugs available for the symptoms of MND, such as pain and muscular spasms, or laxatives if constipation occurs.
Cure:
There is no cure for Motor Neurone Disease; however there are a few drugs in existence and production that extend the lifespan of sufferers. The Stem Cell research initiative could prove to yield results on the front of Motor Neurone disease. By using the artificial embryos to create stem cells that carry the genetic defects responsible for the condition and converting the stem cells into neurons, scientists may be able to unravel how the disease destroys nerves and identify drugs to stop or reverse the damage.
There is a test for mutations in the SOD1 gene that may be helpful in identifying people that may get the disease in later life. However, not all people with mutations on SOD1 have the disease and not all patients with the disease have these mutations.
Genetic Engineering:
Using gene therapy, it may be possible to extend the lifespan of sufferers, and slow the onset of Motor Neurone Disease. According to a study on affected mice, after treatment they are shown to live up to 80% of their natural lifespan. Continued research may see such treatment applied to human sufferers.
For Further Information:
http://en.wikipedia.org/wiki/Motor_Neurone_Disease
http://hcd2.bupa.co.uk/fact_sheets/html/motor_neurone_disease.html
http://news.bbc.co.uk/1/hi/health/600210.stm
http://www.guardian.co.uk/zurichfuturology/story/0,,1920337,00.html
http://abc.net.au/science/news/health/HealthRepublish_1322604.htm
http://www.mnd.asn.au/testing.html
