Study Finds that an Abnormality in RNA May Lead to Congenital Myotonic Dystrophy
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, all characterized by gene mutations. Each type affect patients differently and in different areas of the body as well as at different ages but it is usually diagnosed in childhood.
This is a disease that typically runs in families, though not everyone is the family may be afflicted with the disease. Everyone in the family is usually 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 or the parents carry the gene, but 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, not 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, and 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 present differently, affect different parts of the body and have different times of onset.
Since muscular dystrophy affects the muscle hence in order to keep the bones strong and functioning as much as possible there may be weakening of joints. In some part of dystrophin protein there is a failure. This is believed to affect message transmittal since the neuron connection is affected. This may cause various neurological deficiencies. In patients with DMD there is error in the exon chains on the dystrophin gene. Thus the proper instructions to create protein dystrophin are lacking. Many cases identified have different mutations of exon chains but the only way to know about them is through genetic testing. Becker dystrophy has a slower rate of declination and is a milder form. Researchers thought that it may be possible to create partially functioning dystrophin protein if the process that happens in Becker organically is applied here. In some forms of MD this protein could be applicable.
The ways the sarcomeres and telomeres impact MD have been researched. Every cell in the body contains telomeres hence they are very important. As people get older the cells start creating copies to replenish themselves. The more the cells replenish themselves, the telomeres will keep becoming shorter and finally will not function well. Cell aging starts at this point. Telomeres help in chromosome organization and replication of cells.
A unit of striated muscle in the human body is called a sarcomere. Some of these are made of muscle fibres that comprise of microfibrils which is made up of thick and thin strand. These are organized in repeating subunits. Each of these are known as sarcomere. The capacity of sarcomere’s to contract is vital. The thick filament is made by myosin and thin filament is made by actin.
Myotonic dystrophy is a common form of MD. This disease is inherited. It can affect men and women equally and throughout the lifetime of the person the symptoms may appear anytime. In the muscles of extremities it may cause weakness but also it can affect other muscles. This disease is slow progressing and eventually causes weakness and in other muscle groups cause lack of function. In the newborn a very serious form of disease Thomsen’s disease may appear. The mothers of such newborn usually have DM.
DM1 is the most common form of DM and it is caused by dystrophin protein kinase gene mutation. This gene is located on the chromosome 19q. This gene is a trineuclotide repeat expansion that causes dynamic mutation. During DNA replication, it is caused by slippage. Over the life of the patient these mutations may have degenerated nerve cell.
Since the symptoms can begin at any point in life hence there are no goal posts for the disease and compared to genetic testing, the diagnostic process of this disease is not difficult. Due to the same goal posts there are no real treatment protocols in place and thus according to the specific needs and symptoms the therapy is tailored. For pregnant women with some form of MD, prenatal testing can be done.
Hopefully new gene therapies can be created through the discovery of RNA processing failure. Thus some form of congenital disease will either halt or prevent. Many women with MD hope that through this research, without passing the congenital defect to the child they can become pregnant