Duchenne's Muscular Dystrophy (Genetic Disorder)

Duchenne's muscular dystrophy is a x-linked recessive disease. It is a fast progressive form that is caused by a mutated gene and occurs mostly in boys. The probability of passing this disease to females and males are different. Since a male has x and y chromosomes, if that child's x chromosome has DMD gene mutation, then the child will inherit Duchenne's muscular dystrophy. (DMD encodes the muscle protein, dystrophin.) On the other hand, a female has two x chromosomes, so if they only have one gene mutation, they are considered a "carrier", but if they have two mutated gene, they will have the disease. Recently, 20% of women who are carriers had symptoms such as, muscle weaknesses, or cardiac abnormalities. Women who are carriers have 50% chance of passing on, and 25% chance of getting babies affected with DMD. Gonadel mosaicism is when a person has 2+ cell populations that differ in genetic makeup of eggs and sperms, and the change in the dystrophin gene is a new genetic change.

The symptoms usually start at ages 1-6. Sitting and standing may become difficult. The loss of pelvic and leg muscles cause replacement of fat in those parts of the body. Muscle decline also happens in the arms, neck, and upper body as well, but it's not as severe as the lower half. Because of this, as they grow, their bones may be deformed or have cardiomyopathy (breathing disorders/ enlarged heart).

There are many diagnosis and prevention for Duchenne's muscular dystrophy. One is taking samples of muscle tissues, or muscle biopsy, to look for abnormal levels of dystrophin protein in muscles. Without muscle biopsy, looking at the body's genetic instructions on a blood sample to look for DMD is another good way of diagnosing. (Creatine kinase is highly concentrated in muscle cells, but the breaking of muscle cells go into the bloodstream, so if they are found there, that could answer whether the person has the disease.) Finding deletion/duplication in gene sequencing may also detect the changes in DMD gene. Family history, blood tests, and muscle biopsy can determine the whether you have the disease or not.

Treatment of Duchenne's muscular dystrophy is aimed at the symptoms. If cardiomyopathy is severe, cardiac transplantation is used, but in most cases, doctors use anti-congestive medications. Medications such as prednisone, a steroid, to improve the strength of the individual. But this medication has many side effects, such as, high blood pressure, weight gain, and delayed growth. Cyclosporine is a medication that has improved clinical function in children, but the use of it is very concerning because of cyclosporine-induced myopathy. Oxandrolone, another medication still being studied, has fewer side effects. To prevent hardening of joints and deformity, physical therapy is essential during the process of medical treatments as well.

Duchenne's muscular dystrophies affect 1 in 3500-5000 newborn males. There are between 400-600 boys in the U.S. born with Duchenn's muscular dystrophy every year. There are also girls affected by this disease, but it is very uncommon. There were shocking amount of cases of this disease in the northern region of England. There isn't a direct answer to this mystery, but all we know is that gene mutations have caused it. But generally, Duchenne's muscular dystrophy can be found all over the globe.

Life expectancy for this specific disease is pretty young because the symptoms, such as cardiomyopathy and muscle decline is dangerous and very unhealthy for the body to endure for long time, so the heart can fail easily. Most don't live over 30, because of the breathing complications.