What Is Micrognathia?

Micrognathia is a condition in which the lower jaw is abnormally small, often small enough to interfere with eating and normal tooth and tongue development. This condition is typically hereditary and may be the only deformity the patient has; it also could accompany other medical problems. It is most often diagnosed in infancy, but treatment is sometimes delayed because the abnormally small mandible tends to correct itself as the patient ages. When the condition leaves the patient unable to eat or breathe, however, treatment typically occurs soon after the diagnosis is made.

In many cases, the parent of an affected infant notices the problem when the baby has trouble eating or breathing efficiently because of the small size of the lower jaw. The condition is not always this severe, so some patients are not diagnosed with micrognathia until they are older, at which point other negative effects may be apparent. For example, the small jaw inhibits proper growth of the tongue, which is likely forced against the roof of the mouth much of the time and may obstruct the airway. Another problem that may only be noticeable after a few years is insufficient room for the teeth, resulting in misalignment. This leads to the need for orthodontic treatment once the structure of the jaw has been fixed.

Those who suspect their child has micrognathia are advised to see a doctor for an official diagnosis, especially if the child cannot eat or breathe properly. Before diagnosing jaw deformities, doctors usually complete a physical examination, followed by X-rays of the skull. Other symptoms also will be noted to ensure it is not caused by or accompanied by other medical conditions. For example, some patients with micrognathia also suffer from progeria, or rapid aging, while others may have Marfan syndrome, which is a connective tissue disorder.

Young patients having trouble eating because of micrognathia may be offered feeding tools, such as a specialized bottle nipple. Such equipment can ensure that they get the nutrients they need without having to endure surgery at a young age — unless immediate surgical treatment is necessary for them to breathe. Surgery is typically put off in young patients because micrognathia sometimes corrects itself as the jaw grows during puberty. In addition, the teeth of young kids are not fully developed, so both jaw surgery and orthodontic remedies are often delayed to avoid having to perform treatment again once the bone structure has changed.