Micrognathia, also referred to as mandibular hypoplasia is a medical condition in which the lower jaw is undersized in comparison with the rest of the face. The difference in the size of the upper and lower jaw creates a massive overbite. It presents itself as a symptom of various genetic craniofacial deformities.
Micrognathia is a congenital deformity (is present at birth), that can also develop later in life. According to the Fetal Medicine Foundation, one in every 1500 children are born with this abnormality. Fortunately, the condition can be identified through ultrasound and your child can be born in a safe environment with all necessary measures.
The medical condition may hinder your child’s ability to feed, breathe, or sleep properly. It may also cause malocclusion (improper alignment of the teeth). Micrognathia often corrects itself with time however, it does not go away on its own, medical intervention is employed.
Causes of Micrognathia
Micrognathia a congenital abnormality that caused by inherited factors or genetic mutations. Disorders associated with micrognathia include:
- Hemifacial Microsomia (Craniofacial Microsomia) – Your baby born with facial asymmetry, with either left or right side of the face underdeveloped. The facial features i.e. the eyes, cheekbones, lower jaw, and neck are smaller than the other side of the face. Hemifacial Microsomia is the second most common craniofacial birth defect after cleft lip and palate. The disorder may be inherited or may occur without any previous history in the family.
- Treacher Collins Syndrome – The disorder is characterized by the deformity of the facial bones and tissues. The level of deformity depends on the severity of the condition, ranging from the underdeveloped jaw, ears, eyes and, cheekbones to cleft lip and palate in severe cases.
- Pierre Robin Syndrome – Without a doubt, The child is born with an underdeveloped lower jaw and a normal-sized tongue. Due to this, there is a risk of the tongue falling back into the throat and blocking the airway of the infant. Children with Pierre Robin Syndrome often have an opening or split in the roof of the mouth as well (cleft lip and palate).
Other Causes list are given below:
- Achondrogenesis – It is a hereditary disorder that’s retards the cartilage and bone development. This results in a small lower jaw, short limbs, narrow chest, and a small torso.
- Nager Syndrome – Children suffering from Nager Syndrome are born with a small lower jaw, underdeveloped cheekbones, cleft palate, small ears, downwards sloping eyes, and the absence of eyelashes and thumbs. They may also have fused or curved fingers and short arms. In rare cases, abnormalities of the kidney, heart, urinary tract, and genitals are also present.
- Progeria – It is a rare genetic mutation that causes your child’s body to age at an accelerated rate. Symptoms often start presenting themself when the child turns two in the form of hair loss, small lower jaw, narrow nose, and large eyes. The average life expectancy for children suffering from progeria is thirteen years.
- Trisomy 13 and 18 – Normally, chromosomes are present in pairs of two and each cell contains 23 pairs of chromosomes. However, in trisomy, there is an extra chromosome present. 13 and 18 represent the number of chromosome pair that has the third chromosome attached to it. Trisomy 13 and 18 can cause severe physical as well as intellectual disabilities.
- Symptoms: Some of the symptoms include extra fingers and toes, cleft lip and palate, small lower jaw, heart defects kidney problems. Infants suffering from the condition often do not live past the age of one.
- Cri-Du-Chat Syndrome – In this syndrome, a piece of chromosome 5 is missing, causing a number of physical and mental abnormalities. Infants have a cry that resembles the sound of a cat, giving the syndrome its very name. Children suffering from Cri-du-chat syndrome have wide-set eyes, small lower jaw, and low-set ears.
Symptoms of Micrognathia
If your child has micrognathia, the symptoms of Micrognathia may present themselves as:
- Smaller lower jaw.
- Difficulty in breathing, which may cause apneic spells (cessation of breathing temporarily).
- Cyanosis (child turns bluish-purple) due to lack of oxygen supply.
- Wheezing, noisy breathing.
- In addition, Trouble falling asleep
- Trouble feeding. Changing the position or using special nipples might be helpful in such conditions.
- Poor weight gain
- Misalignment of teeth
- Difficulty in biting and chewing
Diagnosis and Treatment of Micrognathia
Ultrasounds and other specialized methods can used to identify micrognathia before birth.
After birth, the doctor may perform a series of physical examinations after looking at your child’s medical history. Based on this, the doctor may recommend an X-ray, CT scan, or sleep study to further evaluate the condition and draw a decisive conclusion.
If your child has micrognathia, chances are the lower jaw will grow to normal size on its own, especially during the pubescent years. However, if this does not happen, surgical and non-surgical treatment options are available. The type of treatment employed depends on the type of underlying condition causing micrognathia and its severity.
Non-Surgical Treatment
Some of the non-surgical and minimum invasive treatment options for micrognathia are as follows:
- Make your child sleep in a prone position, flat on his/her belly with the chest down and back up. This positioning relieves the airway obstruction by allowing the mandible and tongue base to fall forward.
- Employing the use of feeding-facilitating techniques and specialized devices for children having difficultly eaten.
- At this time, Using positive pressure ventilation by non-invasive interface means to treat obstructive sleep apnea.
- Inserting nasopharyngeal airways into the nasal passage to facilitate breathing.
Surgical Treatment
Depending on the craniofacial disorder your child has, the doctor may recommend surgical intervention.
- Mandibular distraction osteogenesis (MDO) is a procedure that slowly elongates the mandible (lower jawbone). It used to relieve airway obstruction observed in severe micrognathia.
- Undoubtedly, Tracheostomy is the most effective method of clearing an obstructed airway in severe micrognathia. A small opening made into the neck so that a tube can be inserted into the trachea.
- Tongue-lip adhesion (TLA) surgery temporarily attaches the tip of the tongue to the bottom lip. This procedure helps your child breathe better by preventing the tongue from falling back and blocking the airway.
Conclusion
The long-term outlook and survival chance for a child with micrognathia depends on the type of disorder causing the condition, the severity of the condition, and how quickly it diagnosed. Children with Trisomy 13 and 18 or Progeria have a lower survival rate than Pierre Robin Syndrome.
Although there is no way to prevent micrognathia, early diagnosis can help save your child’s life. Your child may require many corrective surgeries, facilitated breathing procedures, modified eating methods, and specialized monitoring.
To conclude, If you or someone in your family has a genetic disorder, consult a genetic counselor for a risk assessment. It will help you determine the chances of passing down the inherited condition to your offspring.