Introduction: Neuromuscular disorders disrupt the function of muscles, motor neurons, peripheral nerves, and neuromuscular connections. The most common neuromuscular disorder and the most severe type of muscular dystrophy is Duchenne muscular dystrophy (DMD), which is caused by a mutation in the dystrophin gene. which is destroyed due to the production of dystrophin in the muscle. Muscles without dystrophin are more sensitive to damage and as a result, in addition to cardiomyopathy, muscle function is also lost.
This disease is an X-linked disease and affects one in every 3,500 to 5,000 male births.
In this article, we have discussed the various features of DMD as a comprehensive review.
Methods: Using the Google Scholar database, articles related to the topic were searched. The search time was selected from 2019 to today using the advanced settings of this database. After studying the found articles, these articles were discussed, categorized and reviewed based on different factors.
Some phrases searched in Google Scholar include; Duchenne disease, genetics of Duchenne disease, clinical symptoms of Duchenne, new treatments for Duchenne, etc.
Results: History of disease discovery:
The first person to describe this disease was Edward Merion. He studied the disease in 9 boys from 3 families and was able to point out some clinical signs of severe muscle wasting. For example, he noticed the enlargement of leg muscles in patients. Later, another scientist named Duchenne glioma investigated a wider spectrum of the disease, and in honor of his knowledge and efforts, the name of this muscular wasting disease, Duchenne, was chosen.
Genetics of the disease:
DMD is a genetic disorder caused by a mutation in the DMD gene. The DMD gene, located on the X chromosome, is the largest known human gene consisting of 79 exons that encode a 3685 amino acid protein called dystrophin.
Since the discovery of the DMD gene in 1987, many different types of mutations have been identified. In a recent analysis, large mutations (affecting more than one exon) were identified in approximately 79% of patients, with large deletions accounting for 68% and large duplications responsible for the remaining 11%.
21% of the remaining patients have small mutations, half of which are nonsense mutations
Although more than 99% of patients with DMD have small deletions, duplications, or mutations, larger genomic rearrangements between an X chromosome and an autosome (non-sex chromosome) have been reported.
Clinical symptoms and diagnosis:
Delay in motor milestones, muscle weakness, hypertrophic calves, Gowers sign (Patients use their hands as support to stand). Cognitive impairment, speech delay, muscle spasms, scoliosis, bone metabolism disorder with mineral depletion. Ossification, visceral smooth muscle involvement, such as delayed gastric emptying and intestinal paralysis, constipation, and gastroesophageal reflux disease (GERD).
treatment:
For decades, scientists have been trying to find effective treatments for this tragic disease. Although there is no absolute cure for DMD, treatments that can delay the onset or slow the progression of the disease have been developed over the past few decades.
Based on the mutation types, several strategies to target dystrophin repair have been proposed years ago and are currently under investigation (eg, premature termination codon mechanism, exon skipping, vector-mediated gene therapy, and myogenic cell transplantation).
Conclusion: DMD is known as a tragic disease because people with it usually have to be confined to a wheelchair by the age of 12. These people usually die in their third decade of life due to respiratory and heart problems.
Considering that this disease does not have a routine and current treatment, it is suggested to pay more attention to the role of genetic counseling and prevention.
Future research should clarify the advantages and disadvantages of new treatment methods for this disease.