A person with an extended chin may have to see a dentist as soon as possible; he may have Prognathism. It is the extension of the jaw that happens when problems in the face bones cause the teeth to be misaligned. It might also be because of genetics, or inherited conditions like Crouzon syndrome or basal cell nevus syndrome.
Possible effects maybe difficulty in talking, biting, or chewing. Treatment can be in the form of orthodontics and surgery, braces, or teeth removal. Here’s a partial list of prominent personalities with this condition: