Duchenne Muscular Dystrophy Overview

Study Notes

Duchenne Muscular Dystrophy

Duchenne muscular dystrophy (DMD) is a severe and progressive muscle-wasting disease, characterized by a deficiency of the dystrophin protein in muscle fibers. The disease leads to progressive muscle degeneration, which can result in difficulty walking, eventual use of a wheelchair, and premature death due to cardiac or respiratory complications.

Etiology

DMD is an X-linked recessive disorder, which means it affects mostly boys, as they inherit the gene from their mothers. Approximately 30% of DMD cases result from new mutations, and the disease has a prevalence of about 1 in 3,600 male infants.

Symptoms and Course

The first signs of DMD usually appear before age 6, and symptoms may include difficulty climbing stairs, a waddling gait, frequent falls, and a tendency to avoid physical activity. The disease progresses rapidly, causing muscle weakness, wasting, and contractures. Patients typically lose the ability to walk between 10 and 12 years of age, and they require assisted ventilation by their early twenties. The median lifespan for patients with DMD is between 20 and 40 years, primarily due to complications involving the heart or lungs.

Diagnosis

DMD is diagnosed through a combination of clinical symptoms, genetic testing, and muscle biopsy. The presence of hypertrophic gastrocnemius muscles and the Gower's maneuver (elevating the body with the arms to rise from the floor) are diagnostic signs. Dystrophin gene analysis confirms the diagnosis.

Treatment

Currently, there is no cure for DMD, and no available treatment can halt its progression. However, several therapies are being explored to address the underlying molecular mechanisms, restore dystrophin production, or alleviate symptoms. These include:

Exon-skipping therapy: This approach aims to restore the missing dystrophin protein by modifying the splicing of the dystrophin gene.
Gene editing: CRISPR/Cas9 technology is being investigated to correct the mutation in the dystrophin gene.
Cell-based therapy: Chimeric cells generated from a patient's own cells and those of a healthy donor have the potential to provide full-length dystrophin and could be a universal therapy for DMD.
Intraosseous transplantation: This technique involves delivering chimeric cells systemically through the intraosseous route to target muscle tissues.

Prognosis

While there is currently no cure for DMD, ongoing research and the development of new therapies offer hope for patients and their families. With improved treatments, patients with DMD may experience a better quality of life and potentially extended lifespans.

Conclusion

While Duchenne muscular dystrophy is a severe and progressive disease, ongoing research and advancements in treatments are leading to a better understanding of the disease and the development of potential therapies to improve the lives of those affected.

Description

Learn about the causes, symptoms, diagnosis, treatment options, prognosis, and ongoing research related to Duchenne muscular dystrophy (DMD), a severe muscle-wasting disease primarily affecting boys. Explore the genetic basis, clinical manifestations, and potential therapies for this progressive condition.