Duchenne muscular dystrophy

Definition

Duchenne muscular dystrophy (DMD) is a severe form of muscular dystrophy that primarily affects boys and is characterized by progressive muscle degeneration and weakness due to the absence of dystrophin, a protein essential for muscle function. This genetic disorder is caused by mutations in the DMD gene located on the X chromosome, making it an X-linked recessive disorder. Understanding DMD provides insights into the complexities of genetic inheritance and its impact on muscle health.

5 Must Know Facts For Your Next Test

1. Duchenne muscular dystrophy typically manifests in early childhood, often between ages 2 and 6, with symptoms like delayed motor milestones, frequent falls, and difficulty climbing stairs.
2. The average lifespan for individuals with DMD has been increasing due to advancements in medical care, but many still face significant health challenges as they age, particularly respiratory and cardiac complications.
3. DMD is diagnosed through genetic testing, muscle biopsy, and clinical evaluation, confirming the absence or mutation of the dystrophin protein.
4. While there is currently no cure for DMD, treatments such as corticosteroids can help slow muscle degeneration and improve quality of life.
5. Gene therapy approaches are being researched as potential treatments for DMD, aiming to restore or replace the function of the dystrophin gene.

Review Questions

• What is the role of dystrophin in muscle function, and how does its absence contribute to the symptoms seen in Duchenne muscular dystrophy?
  • Dystrophin is crucial for maintaining the structural integrity of muscle fibers. It links the cytoskeleton of muscle cells to the extracellular matrix, providing stability during muscle contraction. In Duchenne muscular dystrophy, the absence of dystrophin leads to increased muscle cell damage during physical activity, resulting in progressive weakness, degeneration, and eventual loss of muscle function over time.
• How does the X-linked recessive inheritance pattern affect the likelihood of Duchenne muscular dystrophy being passed from parents to children?
  • Since Duchenne muscular dystrophy is an X-linked recessive disorder, it primarily affects males who inherit one affected X chromosome from their carrier mother. Females can be carriers if they inherit one mutated X chromosome but typically do not exhibit symptoms due to having a second normal X chromosome. This means that each son of a carrier mother has a 50% chance of having DMD, while daughters have a 50% chance of being carriers.
• Evaluate the impact of recent advancements in gene therapy on potential future treatments for Duchenne muscular dystrophy.
  • Recent advancements in gene therapy have opened new avenues for treating Duchenne muscular dystrophy by targeting the underlying genetic cause. Researchers are exploring techniques such as exon skipping and gene replacement to restore functional dystrophin production. These innovative approaches hold promise for not only slowing disease progression but potentially reversing some symptoms, offering hope for improved outcomes and quality of life for those affected by DMD.

Related terms

Dystrophin: A protein that helps maintain the structural integrity of muscle cells; its absence in Duchenne muscular dystrophy leads to muscle damage and degeneration.

X-linked recessive inheritance: A mode of genetic inheritance where a mutation in a gene on the X chromosome causes the phenotype to be expressed in males who have one X chromosome and females who have two mutated copies.

Muscular dystrophy: A group of genetic disorders characterized by progressive weakness and degeneration of the skeletal muscles that control movement.