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Micrognathia (Small Lower Jaw) - Causes, Symptoms, Diagnosis, and Treatment

Published on Jan 11, 2021   -  4 min read


Micrognathia (small jaw or mandibular hypoplasia) is when a child is born with or develops a smaller than normal lower jaw. Read about its causes, diagnosis, and treatment.


What Does Micrognathia Mean?

Micrognathia, otherwise called small jaw or mandibular hypoplasia, is when a child is born with or develops a smaller than normal lower jaw or mandible. The lower jaw of such a child is much shorter and smaller as compared to the rest of the face. It can be seen at birth or develop later in life. Micrognathia is associated with various syndromes, such as fetal alcohol syndrome, Pierre Robin syndrome, Treacher Collins syndrome, hemifacial microsomia, Stickler syndrome, etc., and genetic conditions like progeria and trisomy 13 and 18. Sometimes, the jaw grows with age, and the problem goes away, but in severe cases, micrognathia can lead to feeding problems, breathing difficulties, and malocclusion (misaligned teeth), as there is not enough space for all the teeth to grow in the small jaw.

Infants with micrognathia may need special nipples and have to be appropriately positioned to feed properly and to prevent cyanosis due to breathing problems. Prognosis depends on how small the jaw is, but outcomes are generally good.

What Are the Causes of Micrognathia?

People with a small jaw are usually born that way. In a few cases, genetic disorders are the cause, and in some, spontaneous genetic mutations are to blame. The following hereditary syndromes have micrognathia as a symptom:

The other syndromes that can result in micrognathia are Marfan syndrome, Möbius syndrome, Prader-Willi syndrome, Silver-Russell syndrome, Wolf-Hirschhorn syndrome, Turner syndrome, etc.

What Are the Symptoms Associated With Micrognathia?

Children with micrognathia often show the following signs and symptoms:

When to Consult a Doctor for Micrognathia?

If your newborn’s jaw looks extremely small or if he or she is having trouble feeding, consult a doctor immediately. As some syndromes and genetic conditions associated with micrognathia are serious, prompt diagnosis and treatment are essential. Sometimes, your doctor might diagnose micrognathia before birth with an ultrasound.

How Does a Doctor Diagnose Micrognathia?

A small lower jaw can be clearly seen when its length is compared to the upper jaw. Once the doctor sees a discrepancy in the mandible size, he or she will conduct a physical examination to look for cleft palate, facial asymmetries, and tongue tie. If needed, the doctor will then order X-rays or a CT scan to define the anatomy of the face and head. A polysomnogram or sleep study might be needed to measure the child’s breathing, oxygenation during sleep, and brain and heart function.

How Is Micrognathia Treated?

The treatment options for micrognathia include:

1) Non-surgical Treatment -

2) Surgical Treatment -

The prognosis for children with micrognathia is generally good, but it can vary based on the severity. Quick diagnosis and treatment, including surgeries, are essential to give the child the best long-term quality of life. The treatment plan will depend on the child’s jaw growth and development. For more information, consult a doctor online now.


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11 Jan 2021  -  4 min read




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