Micrognathia

What is Micrognathia?

Micrognathia is a condition in which the lower jaw (mandible) is abnormally small or underdeveloped. This can lead to several functional and cosmetic challenges, including difficulty breathing, feeding, and speaking, depending on the severity of the condition.

Micrognathia may occur as part of a condition called Pierre Robin sequence, where the small jaw causes the tongue to be displaced up and back in the mouth. This displacement of the tongue can result in a cleft palate and breathing difficulties.

Prevalence:

Micrognathia can occur as part of various genetic conditions, congenital syndromes, or developmental abnormalities. It is relatively rare but can be seen in approximately 1 in 3,000 to 5,000 live births. 

Symptoms:

The severity of micrognathia varies, but common symptoms may include:

  • Feeding difficulties including difficulty latching or sucking effectively
  • Respiratory problems particularly in newborns because of the compromised airway
  • Speech and dental issues can develop because a small jaw can affect the alignment of teeth and proper speech development.
  • Facial appearance where the chin appears recessed or the lower jaw is noticeably smaller than normal.

Causes:

Micrognathia can be caused by:

  1. Genetic conditions or Chromosomal abnormalities such as:
    • Down Syndrome, Trisomy 18, 22q11.2 Deletion Syndrome, Stickler Syndrome, and others which can cause symptoms in multiple body systems, including micrognathia.
  2. Environmental factors: Certain external factors such as maternal infections, drugs, or alcohol consumption during pregnancy could contribute to the development of micrognathia.

Diagnosis:

Micrognathia is often diagnosed and further evaluated through:

  1. Physical examination: A healthcare provider may notice a small jaw or a recessed chin.
  2. Prenatal ultrasound: During routine prenatal scans the condition can be detected if it is severe enough to affect facial appearance.
  3. Imaging: X-rays or CT scans of the skull and jaw may be performed to assess the structure of the bones.
  4. Evaluation for associated conditions: If micrognathia is suspected, doctors will also look for other related abnormalities (e.g., cleft palate, breathing issues, etc.).

Treatment:

Treatment for micrognathia depends on the severity and underlying cause of the condition:

  1. Breathing support: In cases where the jaw restricts airway function, infants may need respiratory support such as a nasal cannula (a small non-invasive device that delivers supplemental oxygen through the nose) or, in severe cases, a tracheostomy (a procedure that creates an opening in the neck and into the windpipe for direct access to the airway).
  2. Feeding therapy: Special feeding techniques or bottles may be used to help with nutrition, especially for infants struggling to latch or feed properly.
  3. Surgical intervention: Surgery may be required to correct the jaw’s position. This may include:
    • Mandibular distraction osteogenesis (MDO): A surgical procedure where the jaw is gradually lengthened to allow for proper growth.
    • Cleft palate repair: Surgery to close the gap, restore palate function, and improve speech and eating. 
  4. Orthodontic care: As the child grows, orthodontic treatment may be necessary to correct dental and speech problems caused by the small jaw.
  5. Speech therapy: Children with speech difficulties may benefit from early speech therapy to address any issues resulting from the small jaw.

Prognosis:

The prognosis for micrognathia depends largely on the severity of the condition and whether it is associated with other health issues. In many cases, micrognathia improves as the child grows. For children with mild micrognathia, the condition may be managed with feeding and breathing support.

However, if micrognathia is part of a syndrome with other serious complications (e.g., heart defects, cleft palate, neurological issues), the prognosis may be more complex and require long-term medical care. Some children may need multiple surgeries or interventions throughout their lives.

 

 

Provided by:  Cincinnati Children’s Hospital Medical Center
Reviewed by: Leandra K. Tolusso, MS, LGC