Muscular Dystrophy (MD) is a group of genetic disorders that cause the muscles of the body to weaken and fail over time. There are different types of MD that are all characterized by gene mutations, and each type affects patients differently and in different areas of the body, as well as at different ages. However, it is usually diagnosed in childhood.
This a disease that typically runs in families. Though not everyone in the family may be afflicted with the disease, they would be a carrier of the gene. When they come in contact with someone else that also has the gene, there’s a fifty percent chance that any offspring of the union will have MD. In the rarest cases it’s possible for spontaneous development of MD when neither of the parents carry the gene where the offspring has a spontaneous mutation in their own genes.
In muscular dystrophy the genes that contain the information that the cells need to make a protein which controls the functions of the muscles have a problem where they’re unable to either create the protein, don’t make enough of the protein or make mutated unusable forms of the protein. For instance, those with Becker and Duchenne muscular dystrophy don’t make enough of the protein dystrophin, which allows muscles to be strong and protects them from injury.
It’s a progressive disease and has no cure. The outcome for most is generally the same. Most that are diagnosed with MD will end up in a wheelchair at some point in their lives. This isn’t a death sentence however, with the right therapies, support and some adaptations to cater to the needs of the disease, many are able to do .
Under the umbrella term of MD there are nine forms of the disease that are presented differently. Below are two types of MD and their symptoms:
This is a disease that affects children and reaches into their adulthood. One of the nine forms of MD, Duchenne usually presents in early childhood between the ages of three and five. Although girls can be affected, it is more prevalent in boys. The disease affects 1 in 3,500 worldwide and most patients are in wheelchairs by the age of fifteen. Because of the way that the lack of dystrophin is believed to affect the neuron connection and message transmittal, those affected are likely to have neurological deficiencies that are wide ranging and include speech, memory, intelligence, attention, mental health and seizures.
The prognosis for children diagnosed with the disorder until recently did not extend beyond the teenage years, but recent improvements in cardiac and respiratory care have seen life expectancy extend for some patients into their thirties, with a few living well into their forties. This expanded adult population prompts the need for implementation of new care and treatment protocols as well as expansion of clinical trials.
Exon chains on the dystrophin gene in patients with DMD contain errors or mutations that manifest as large deletions in chains, resulting in missing exons, duplication of the same exons, or minor deletions and duplications. So the exons don’t fit together well. Consequently, it lacks the proper instructions to create the dystrophin protein that helps muscles work the way that they should. Over eighteen hundred different mutations of the exon chains have been identified but the only way of knowing which mutations affect a patient is through genetic testing, knowing the specific mutations and deletions on individual dystrophin genes helps in tailoring treatment plans and makes managing care easier.
Approximately two thirds of people that are affected by DMD have deletions and duplications of the exons on the dystrophin gene, the rest of the population are likely the result of not easily identifiable point mutations.
OPMD typically presents after the age of forty. Like most Muscular Dystrophy (MD) diseases, it’s a slow progressing disease that affects the muscles of the upper eyelid and throat, leading to ptosis or drooping eyelids, as well as dysphagia or difficulties in swallowing. In some cases the disease may affect other areas of the body such as the upper legs and arms, eventually affecting the legs enough that walking may become difficult over time.
Both of the symptoms associated with the eyes and throat can be managed or corrected with surgery, but commonly recur between five and fifteen years of the procedure. There are two types of OPMD based on how they are inherited: autosomal dominant and autosomal recessive. Both are mutations of the PABPN1 gene. OPMD is one of the nine major forms of MD but is also one of the more rare forms of MD.
Some populations are more at risk than others for inheriting the disease. By distribution the disease affects populations in twenty-nine countries across the world, with the highest incidences clustered in the French-Canadian Quebecois population at one in one thousand, the Bukhara Jewish central Asian population of Israel and the Latino population of New Mexico. Reports have also indicated that in Europe the disease is prevalent in the native French population at a one in one hundred thousand occurrence. In all these populations the autosomal dominant inheritance form of the disease is more common than the recessive which is a rare form of inheritance.
Most incidences of OPMD are autosomnal where an autosomal dominant inheritance means that at least one copy of a gene were received from parents and the likelihood that the will be expressed is at least fifty percent. One abnormality within the first twenty-two autosomal chromosomes can cause the disease or disorder even if a normal gene is inherited from the other parent as the abnormal gene is the dominant one.
It can be difficult for a once very active individual with MD when the muscles start to fail them. Having a full life with the disease can be challenging, someone who was able to run five miles now has trouble walking a few feet without getting winded, but with adaptations their challenges can become benchmarks for success.
Because the disease affects the muscles this can sometimes be accompanied by secondary problems that involve the weakening of the joints in order to keep the muscles as strong and functioning for as long as possible, MD patients need to enlist the aid of physical and rehabilitation specialists who can create safe structured exercise programs that take into account their particular limitations and strengths.
MD patients can also take part in recreational sports such as skiing with specially designed skis and equipment for those with impaired leg strength and balance issues. Wheelchair hockey is another popular sport that allow MD patients to participate via different types of hockey sticks that take into account the individual's upper body capabilities. These are just a few of the sports along with wheelchair rugby, tennis and bowling that MD patients can enjoy.
Even while the social and emotional aspect of these activities shouldn’t be discounted, the take away from MD patients participating is that while they do something that they love, they’re also using exercise to keep their bodies in a healthier state for as long as they can.
MD patients can lead full lives doing just about anything and many choose to enter the arts. Like just about everyone else MD patients love music too. Their limbs may not always allow them to participate in the way they would like to, but that doesn't have to stop the passion they feel for the music or sports or anything else that they love.
Some MD patients choose a life of service, opting to use their disease to raise awareness of the disease and bring education to people who may not have knowledge of what MD is. They raise funding for research in the disease while also giving back to younger members of the MD community in the form of encouragement and inspiration.
Thanks to new therapies, people with MD are living longer lives. Some have gone off to university, gotten married and started families of their own. People with MD can enjoy the same things that people without the disease do, they may go a little bit slower and do things somewhat differently, but their lives are filled with great experiences as well.