Micrognathia

Alternative names:

receding chin; under-bite

Definition:

A relative term describing the small size of the lower jaw.

Considerations:

In true micrognathia, the jaw is small enough to interfere with feeding of the infant and may require special nipples in order to feed adequately.

Micrognathia may occur as the only abnormality in a child, and is often self-correcting during growth, especially at puberty when the jaw grows significantly. It may also be associated with certain inherited disorders and syndromes.

Micrognathia is one cause of abnormal alignment of the teeth (malocclusion).

Common causes:

• Pierre Robin syndrome
• Hallerman-Streiff syndrome
• trisomy 13
• trisomy 18
• X0 syndrome (Turner's syndrome)
• progeria
• Treacher-Collins syndrome
• Smith-Lemli-Opitz syndrome
• Russell-Silver syndrome
• Seckel syndrome
• cri du chat syndrome
• Marfan's syndrome

Note: There may be other causes of micrognathia. This list is not all inclusive, and the causes are not presented in order of likelihood. The causes of this symptom can include unlikely diseases and medications. Furthermore, the causes may vary based on age and gender of the affected person, as well as on the specific characteristics of the symptom such as quality, time course, and associated complaints. Use the Symptom Analysis option to explore the possible explanations for micrognathia, occurring alone or in combination with other problems.