We talk about muscular dystrophy to refer to a set of diseases that cause the progressive deterioration of the muscles, making them weak and rigid. Duchenne muscular dystrophy is one of the most frequent of this group of disorders.
In this article we will describe what Duchenne muscular dystrophy is, what causes it, what its most characteristic symptoms are and how they can be treated and alleviated from a multidisciplinary perspective.
- You may be interested in: “The 15 most common neurological disorders”
What is Duchenne muscular dystrophy?
Pseudohypertrophic or Duchenne muscular dystrophy is a degenerative disease of the muscles. As the condition progresses, the muscle tissue weakens and its function is lost until the person becomes totally dependent on their caregivers.
This disorder was described by Italian physicians Giovanni Semmola and Gaetano Conte in the first half of the 19th century. However, its name comes from the French neurologist Guillaume Duchenne, who examined the affected tissue on a microscopic level and described the clinical picture in 1861.
Duchenne disease is the most common type of childhood muscular dystrophy , affecting 1 in 3600 boys, while it is rare in girls. There are nine types of muscular dystrophy, a condition that gradually weakens the muscles and makes them stiff.
Life expectancy for people with this disorder is about 26 years, although medical advances allow some people to live more than 50 years. Death usually occurs as a result of breathing difficulties.
Signs and symptoms
Symptoms appear in early childhood, between approximately 3 and 5 years of age. Initially, children with this disease have increasing difficulty in standing and walking due to the involvement of the thighs and pelvis. In order to stand up, it is common that they have to use their hands to keep their legs stretched and to lift themselves up.
The pseudohypertrophy characteristic of Duchenne’s dystrophy occurs in the muscles of the calves and thighs, which become enlarged by the time the child starts walking, basically due to the accumulation of fat. This developmental milestone usually occurs late in Duchenne cases.
Later the weakness will generalize to the muscles of the arms, neck, trunk and other parts of the body, causing contractures, imbalance, gait disturbances and frequent falls. The progressive muscle deterioration means that towards the beginning of puberty, children diagnosed lose the ability to walk and are forced to use a wheelchair .
Lung and heart problems are common as secondary signs of muscular dystrophy. Respiratory dysfunction makes coughing difficult and increases the risk of infection, while cardiomyopathy can lead to heart failure. Scoliosis (abnormal curvature of the spine) and intellectual disability also sometimes occur.
- You may be interested in: “Parkinson’s: causes, symptoms, treatment and prevention”
Causes of this disease
Duchenne muscular dystrophy is caused by a mutation in the gene that regulates dystrophin transcription , a protein essential for the maintenance of the structure of muscle cells. When the body cannot properly synthesize dystrophin the muscle tissues progressively deteriorate until they die.
Wear and tear on muscles occurs as a result of intensified oxidative stress reactions, which damage the muscle membrane to the point of cell death or necrosis. Subsequently, the necrotic muscle is replaced by adipose and connective tissue.
This disease is more common in men because the gene that causes it is located on the X chromosome ; unlike women, men have only one of these chromosomes, so their defects are less likely to be corrected spontaneously. Something similar happens with some forms of colorblindness and hemophilia.
Although 35% of the cases are due to “de novo” mutations, the genetic changes in Duchenne muscular dystrophy are usually transmitted from mother to child . Boys who carry the defective gene have a 50% chance of developing the disease, while it is rare for girls and when this happens the symptoms are usually milder.
Treatment and intervention
Although no treatments have been found to cure Duchenne muscular dystrophy , multidisciplinary interventions can be very effective in delaying and reducing symptoms and in increasing the quality and life expectancy of patients.
Among the pharmacological treatments of this disease the use of corticosteroids such as prednisone stands out. Some studies suggest that the use of these drugs prolongs the ability to walk for 2 to 5 years more.
The regular practice of physical therapy and gentle exercise (such as swimming) can limit the deterioration of the muscles, since inactivity increases their affectation. Also, the use of orthopaedic instruments such as braces and wheelchairs increases the level of independence of patients.
Because of the association of Duchenne dystrophy with cardiac and respiratory problems, it is important that people diagnosed with it visit cardiologists and pulmonologists with some frequency. The use of beta-blocker drugs and assisted breathing devices may be necessary in many cases.