This link has a ton of good information in regards to Duchenne Muscular Dystrophy. Hope this helps.
https://ghr.nlm.nih.gov/condition/duchenne-and-becker-muscular-dystrophy#inheritance
If a mother has a child with Duchenne Muscular Dystrophy, but she is not a carrier (de novo mutation), are the chances that her future offspring will also be affected increased?