There are several possible reasons for this. Because genetic inheritance is random, your DNA doesn’t match other family members’ DNA exactly, so neither will your regions. Your parents’ connection to their Genetic Communities™ will likely be stronger than your connection because they're a generation closer to the ancestors of the Genetic Community, which is another reason they might have a region you don’t. Or maybe you didn’t inherit enough segments of the DNA that connect one of your parents to a Genetic Community, so the region associated with that Genetic Community doesn’t appear in your DNA Story.