How is Duchenne muscular dystrophy inherited?

Duchenne muscular dystrophy (DMD) is an X-linked genetic condition caused by mutations in the DMD gene located on the X chromosome. Because of this inheritance pattern, the disease primarily affects males.123

The transmission of the disorder occurs as follows:
* Carrier Mothers: A female who carries the mutation has a 50 percent chance of passing the gene to each of her sons, who will then develop the disease, and a 50 percent chance of passing it to each of her daughters, who will become carriers. While female carriers typically do not manifest the full disease, they may experience muscle fatigue and cardiomyopathy.12
* Spontaneous Mutation: Approximately 30 percent of DMD cases are not inherited from a parent but are the result of a spontaneous genetic mutation, meaning there is no prior family history of the disorder.1

The absence of the protein dystrophin, which results from these mutations, leads to the progressive degradation of muscle cells.12