Prognathism: what is it and how to recognize it?

What is Prognathism?

Prognathism refers to a protruding jaw. It is also called an extended chin or Habsburg jaw. The condition is usually a sign of an underlying condition. Talk to your doctor if you suspect your jaw is protruding.

Recognizing Prognathism

You have mandibular prognathism if your bottom jaw extends further out than it should. Maxillary prognathism occurs when your upper jaw protrudes. In bimaxillary prognathism, both jaws stick out further than the rest of your face.

Underlying Causes of Prognathism

Some people are born with a protruding upper or lower jaw without having any underlying conditions. In others, it can be associated with one of the following underlying conditions:


This condition occurs when your body produces too much growth hormone (GH), which causes your tissues to enlarge. Your lower jaw ends up sticking out as it becomes larger. According to the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), it affects about 60 out of every one million people (NIDDK, 2012).

Basal Cell Nevus Syndrome

This is a rare inherited condition that causes abnormal facial characteristics, such as a broad nose, eyes that are too far apart, and a heavy brow. Prognathism occurs in some cases.


This is a very rare condition that people are born with. It can cause shortened arms and legs, hearing problems, a short nose, a protruding jaw, and mental retardation.

When to See the Doctor

Prognathism can cause a condition called malocclusion of the teeth, which means that your teeth are not aligned correctly. This can cause problems with biting, chewing, and talking. Misaligned teeth are also harder to clean, which increases your risk of gum disease and tooth decay. Your dentist can check your jaw alignment and refer you to an orthodontist for treatment.
In some cases of Acromegaly, Basal cell nevus syndrome and Acrodysostosis you should see a doctor from time to time.

Treating Prognathism

Dental Care

An orthodontist can fix a protruding jaw through orthognathic surgery. You can have this done to correct misaligned teeth or for cosmetic reasons. You will have to wear braces to encourage your teeth to move into their new position.

Medical Care

Your doctor can diagnose and treat any underlying conditions that are causing your protruded jaw.

Preventing Prognathism

You cannot prevent it due to genetic conditions, such as basal cell nevus syndrome. You can talk to a genetic counselor if you are planning on having children to find out if there is a the chance of passing the condition on to them.


Book your appointment with our Orthodontist Dr. Madeleine Smit or with our Maxillofacial Surgeon, Dr. Alejandro Mazzaro.

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