ADAM Health Encyclopedia

Micrognathia

Definition

Micrognathia is a term that describes an abnormally small lower jaw.

Considerations

In true micrognathia, the jaw is small enough to interfere with the infant's feeding. Infants with micrognathia may need special nipples in order to feed properly.

Micrognathia may be the only abnormality in a child. It often corrects itself during growth, especially at puberty when the jaw grows quite a bit. It also can be caused by certain inherited disorders and syndromes.

Micrognathia is one cause of abnormal alignment of the teeth. You can see this in the way the teeth close. Often there will not be enough room for the teeth to grow. Talk to an orthodontist when the child's adult teeth come in. At times, children can outgrow micrognathia, and it makes sense to wait to treat the condition until they are older.

Causes

• Pierre Robin syndrome
• Hallerman-Streiff syndrome
• Trisomy 13
• Trisomy 18
• X0 syndrome (Turner syndrome)
• Progeria
• Treacher-Collins syndrome
• Smith-Lemli-Opitz syndrome
• Russell-Silver syndrome
• Seckel syndrome
• Cri du chat syndrome
• Marfan syndrome

Home Care

If micrognathia interferes with feeding, you'll need to use special feeding techniques and equipment. You can learn these techniques through special programs that are available at most hospitals.

When to Contact a Medical Professional

Contact your health care provider if:

• Your child seems to have a very small jaw.
• Your child has trouble feeding properly.

The doctor will do a physical examination and may ask questions about the history of the problem, such as:

• When did you first notice that the jaw was small?
• How severe is it?
• Does the child have trouble eating?
• What other symptoms are present?

The physical examination will include a thorough check of the mouth.

The following tests may be performed:

• Dental x-rays
• Skull x-rays

If there are other symptoms that indicate an inherited condition, testing for that condition may be advised. The health care provider might recommend surgery or orthodontic devices.