Phenotype predictions for exon deletions/duplications: A user guide for professionals and clinicians using Becker and Duchenne muscular dystrophy as examples.

Variations in the DMD gene that affect dystrophin production underlie both the severe Duchenne and the milder Becker muscular dystrophies (DMD and BMD, respectively). Depending on their location, deletions and duplications involving one or more exons of a gene can have a range of consequences. This overview, summarizing the important points to consider, was drafted in response to frequent questions we receive about deletions/duplications involving the dystrophin encoding DMD gene. Although directed at DMD, the observations made can be applied to many other genes. The overview is meant primarily for healthcare professionals involved with interpreting the results of genetic analyses in clinical practice.