I am not someone who knows a lot about this, but so far i learned that developmental disorders are defined as conditions that begin in the early stages of brain development, usually prenatal or early childhood, while PTSD and trauma related changes are considered acquired conditions (which means that they can happen at any age, even in adulthood).
Even if the brain changes, those changes will be a response to environmental events, not an natural path of development. Yet i'm sure that if trauma happens during childhood it can interfere with normal development in a lasting way.