Duchenne muscular dystrophy is characterized by which type of mutation?

Duchenne muscular dystrophy (DMD) is primarily caused by mutations in the dystrophin gene located on the X chromosome, which is crucial for maintaining the structural integrity of muscle cells. The most common mutations that lead to DMD are deletions or insertions that result in a frameshift in the reading frame of the gene. When a frameshift mutation occurs, the codons downstream of the mutation are altered, leading to the production of an entirely different (and usually nonfunctional) protein.

This disruption in the reading frame can prevent the synthesis of dystrophin or create a shortened, ineffective version of the dystrophin protein, which cannot perform its necessary functions in muscle cells. As a result, the muscle cells become more susceptible to damage, ultimately leading to the characteristic muscle degeneration seen in DMD.

While point mutations, simple deletions, and failures in nucleotide excision repair can cause a variety of genetic disorders, they are not the primary mutations associated with Duchenne muscular dystrophy. In DMD, the deletion or insertion of nucleotides that leads to a frameshift is a critical aspect of the disease's pathology.