What are the main types of genetic alterations? There are three main alterations that can occur in the dystrophin gene resulting in Duchenne: Deletions Account for the majority of alterations in duchenne, causing sections of the dystrophin gene to be missing. Duplications Sections of the dystrophin gene are copied resulting in a altered dystrophin gene. Nonsense mutations/Point mutations/ other small changes Point mutations are small alterations in the dystrophin gene. Small alterations include nonsense mutations where the instructions for making dystrophin are shorter than normal, leading to production of incomplete dystrophin.