A double chin occurs when a subcutaneous sheet of fat around your neck sags and causes a wrinkle. Many families suffer from a hereditary predisposition to them. Some families naturally retain too much water in the chin area, and others naturally store excess fat. Age is another cause.
A turkey neck can be the result of several different factors, which include the natural aging process or extreme fluctuation in weight. There are some cases of this excess skin that are the cause of genetics.