Duchenne muscular dystrophy (DMD) is a genetic disorder and the most severe form of muscle diseases with a degenerative nature. It is hereditary and sex related. While it occurs almost exclusively in boys, women are carriers of the mutated gene. Rarely, this disorder can occur within a family with no history of DMD, due to the chance that it was somehow not properly diagnosed, or to accidental new genetic mutation that may have happened in a woman’s egg cells. A recent study conducted by a team of The Research Institute at Nationwide Children’s Hospital brings new hope for Duchenne Muscular Dystrophy patients when it comes to therapy drugs for this severe disorder.
According to The National Human Genome Research Institute, the number of people affected with this disease is around 1 in 3,500 male births worldwide. Due to the gene mutation, muscles of people with DMD are in total lack of the protein called dystrophin – important in the process of muscles contraction. Deficiency of the dystrophin causes damage to the muscle fibers, and eventually leads to the weakening and deterioration of muscle mass, which becomes replaced with fat.
A new drug, called eteplirsen, currently on clinical trial, is designed to overlook the missing parts of the gene and therefore, to induce the patient’s body to produce the absent protein. The research included 12 boys diagnosed with DMD, age 7 to 12 years, divided in three groups – two of them received the drug in different amounts, and the third was the placebo-group. But, due to significant progress in first two groups registered after 24-week of receiving the drug, and the fact that no side effects were shown, even the control group started taking the eteplirsen from this point of the study. Concretely, new hope that this drug brings to the people with Duchenne Muscular Dystrophy was registered in the overall result of a 52 percent increase in dystrophin-positive muscle fibers after 48 week of receiving the drug, than the patients had at the start of the clinical trial. This also manifested through the possibility to walk farther that the placebo group on the walk-test used in the study, a whole 67.3 meters farther.
“I’ve been doing this for more than 40 years and this is one of the most exciting developments we’ve seen,” said the lead author of the study published in the journal Annals of Neurology, Jerry Mendell, MD.
These results are especially encouraging when we know that medicine, at least for now, cannot influence the causes of Duchenne muscular dystrophy, so currently the treatment is symptomatic. Usually, the first symptoms can be seen when a child is between 3 and 5 years old and the irregularity can be observed when a child is running and jumping. Parents should contact a pediatrician if they notice that a child is clumsy and falls often, have difficulties climbing stairs, getting up from the floor or running, has enlarged calf muscles.
The weakness develops progressively and is more prominent in the legs and the pelvis, than in the shoulder area. By the age of 10 the majorities of children with DMD starts using braces, and to the age of 12 most are confined to a wheelchair. Life expectancy in these patients is around 25 years, mainly because of the breathing complications and cardiomyopathy, but thanks to medical headway it is gradually becoming longer.
With this being said, the clinical trials of this new drug are really encouraging. Since the study sample was small, there are numerous open questions regarding this promising treatment, but, like Dr. Mendell said: “It offers great hope to patients with Duchenne muscular dystrophy and their families.”
By: Milica Zujko