page_title: Duchenne muscular dystrophy
section_title: Gene therapy
hierarchical_section_title: Duchenne muscular dystrophy / Research / Gene therapy
caption_attribution_description: English: graphical overview of CRISPR Cas9 plasmid construction
context_page_description: Duchenne muscular dystrophy is a severe type of muscular dystrophy that primarily affects boys. Muscle weakness usually begins around the age of four, and worsens quickly. Muscle loss typically occurs first in the thighs and pelvis followed by the arms. This can result in trouble standing up. Most are unable to walk by the age of 12. Affected muscles may look larger due to increased fat content. Scoliosis is also common. Some may have intellectual disability. Females with a single copy of the defective gene may show mild symptoms.
  The disorder is X-linked recessive. About two thirds of cases are inherited from a person's mother, while one third of cases are due to a new mutation. It is caused by a mutation in the gene for the protein dystrophin. Dystrophin is important to maintain the muscle fiber's cell membrane. Genetic testing can often make the diagnosis at birth. Those affected also have a high level of creatine kinase in their blood.
  Although there is no known cure, physical therapy, braces, and corrective surgery may help with some symptoms. Assisted ventilation may be required in those with weakness of breathing muscles.
context_section_description: Researchers are working on a gene editing method to correct a mutation that leads to Duchenne muscular dystrophy (DMD). Researchers used a technique called CRISPR/Cas9-mediated genome editing, which can precisely remove a mutation in the dystrophin gene in DNA, allowing the body's DNA repair mechanisms to replace it with a normal copy of the gene. The benefit of this over other gene therapy techniques is that it can permanently correct the "defect" in a gene rather than just transiently adding a "functional" one.
  Genome editing through the CRISPR/Cas9 system is not currently feasible in humans. However, it may be possible, through advancements in technology, to use this technique to develop therapies for DMD in the future. In 2007, researchers did the world's first clinical (viral-mediated) gene therapy trial for Duchenne MD.
  Biostrophin is a delivery vector for gene therapy in the treatment of Duchenne muscular dystrophy and Becker muscular dystrophy.
caption: CRISPR overview
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