At a Glance
Micrognathia is a condition in which the lower jaw is smaller than normal, which can push the tongue backward and narrow the airway. This structural difference may cause feeding or breathing difficulties in infants and can increase the risk of obstructive sleep apnea by making the airway more likely to collapse during sleep.
Micrognathia, or an undersized lower jaw, can affect the structure of the airway and may increase the risk of sleep apnea. Although it's relatively rare — occurring in about 1 in every 1,500 newborns — it can impact breathing, especially during sleep. Because a smaller or recessed lower jaw can cause the tongue and surrounding tissues to sit farther back in the throat, it may narrow the airway and make it more prone to collapse.
Children with micrognathia are particularly susceptible to obstructive sleep apnea (OSA), but the condition can also affect breathing in adolescents and adults, depending on its severity. Understanding how micrognathia influences the airway can help with early recognition of symptoms and guide appropriate evaluation and treatment.
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What Is Micrognathia?
Also called mandibular hypoplasia, micrognathia refers to a small lower jaw. Micrognathia is frequently associated with underlying health conditions, including over 700 genetic syndromes. In syndromes that cause micrognathia, children may also have a cleft palate or changes in the central nervous system, spine, limbs, hands, or ears.
Micrognathia can result in a variety of health complications. Newborns with micrognathia may have difficulty with feeding and require specialized approaches. Micrognathia can also cause difficulty breathing and is frequently associated with obstructive sleep apnea in infants.
In older children, micrognathia can affect appearance, but typically doesn't cause medical issues or complications. In rare cases, micrognathia may develop after childhood due to injury or conditions that affect the joints and tissues around the lower jaw.
How Are Sleep Apnea and Micrognathia Connected?
Micrognathia increases the risk of obstructive sleep apnea in children because the small size of the jaw narrows the airway and reduces the space needed for breathing. The small lower jaw may not allow enough room for the tongue, which can fall to the back of the throat and block the airway during sleep.
Obstructive sleep apnea is a medical condition in which a sleeping person’s airway becomes repeatedly blocked, causing disrupted breathing. Without treatment, OSA can lead to serious health complications and affect a child’s growth, mood, and behavior. It can also cause or exacerbate long-term health problems.
While OSA affects only 1% to 5% of children in the general population, around 88% of children with micrognathia have OSA. Micrognathia may also increase the risk of severe OSA, meaning more than 10 episodes of disrupted breathing for each hour of sleep.
What Causes Micrognathia?
While mild cases of micrognathia may be passed down within families through genetic inheritance, more severe cases are often caused by new genetic changes found only in the child and not in either parent.
Approximately one-third of people with micrognathia have an underlying genetic condition. Micrognathia is associated with over 700 genetic syndromes, including:
- Fetal alcohol syndrome
- Pierre Robin syndrome
- Trisomy 9
- Trisomy 13
- Trisomy 18
How Is Micrognathia Diagnosed?
Doctors typically diagnose micrognathia early in a child’s life or even before they are born. A physician may be able to detect micrognathia as soon as the first trimester, based on ultrasound images.
A doctor may also assess a child for micrognathia if they appear to have an undersized jaw or if they have difficulty feeding. For instance, an infant with micrognathia may have trouble breastfeeding because their tongue position can keep them from latching properly.
If a doctor suspects micrognathia, they may perform a thorough physical exam to evaluate the jaw and mouth. The provider may also recommend imaging of the head and dental x-rays.
Based on the doctor’s finding, they may refer the family to a geneticist, who can conduct testing to identify any underlying genetic conditions in the parents and child.
How Is Micrognathia Treated?
Treatment for micrognathia can depend on the condition’s severity, underlying cause, and whether the child has difficulty breathing or eating. Depending on its cause, micrognathia may resolve on its own as the jaw grows. For this reason, parents may choose to postpone treatment and wait to see if the problem corrects itself.
In infants with mild micrognathia, complications may be managed by changing feeding and sleep positions. In older children, orthodontic treatment may help correct problems with alignment of the teeth and a child’s bite.
In more severe cases, the doctor may recommend additional treatment to keep the airway open. Treatment may include surgery or continuous positive airway pressure (CPAP) therapy.
- Continuous positive airway pressure: Continuous positive airway pressure (CPAP) therapy can also be a highly effective treatment for the symptoms of obstructive sleep apnea in children with micrognathia. A CPAP machine pumps pressurized air through a face mask to keep the airway open.
- Surgery: Several types of surgery can treat severe obstructive sleep apnea in children. One procedure, called mandibular distraction osteogenesis, lengthens the jaw. Less-common surgical interventions include tracheostomy and tongue-lip adhesion.
Medical Disclaimer: This content is for informational purposes and does not constitute medical advice. Please consult a health care provider prior to starting a new treatment or making changes to your treatment plan.
Written by
Amber Garnett, Contributing WriterAmber is a freelance writer who resides in Seattle. Amber has worked as a clinical social worker in the medical field for over a decade. She loves long nature walks, traveling and reading poetry.
Reviewed by
Howard J. Hoffman, DDS, Medical ReviewerDr. Howard J. Hoffman is a dentist specializing in dental sleep medicine and the treatment of obstructive sleep apnea and temporomandibular joint (TMJ) disorders. With more than four decades of experience in dentistry and over 25 years focused on sleep apnea treatment, he works with physicians and sleep specialists to help patients manage sleep-disordered breathing using oral appliance therapy.
