The Flawed Child

When a child is born with a serious flaw in her character caused by an imbalance of chemicals in her mind making her incapable of controlling her actions and emotions, it can be dangerous to her as well as others.
This story depicts a child who is born with such a flaw, but hides it well. Her family senses she is different, but find it difficult to accept as they see small clues that are quickly hidden.