Prognathism is an extension or bulging out (protrusion) of the lower jaw (mandible). It occurs when the teeth are not properly aligned due to the shape of the face bones.

What causes prognathism?

Causes of Prognathism

Acromegaly, excessive production of growth hormone in a patient's body leading to enlarged tissues of their lower jaw. Basal cell nevus syndrome, an inherited characteristic or Crouzon syndrome which is marked by premature fusion of skull bones, giving rise to the abnormal and unhealthy jaws.

What does prognathism look like?

Overview. If your jaw protrudes, it's known as prognathism. This trait is sometimes called extended chin or Habsburg jaw. Typically, prognathism refers to the lower jaw sticking out more than usual.