Micrognathia: Causes, Symptoms, Treatment, Prevention, Diagnosis

Micrognathia is a condition identified by a small lower jaw. A child suffering from this medical condition has a much smaller lower jaw as compared to the rest of the face. It occurs in the 4th week of the fetal gestation due to insufficiency in the movement of neural crest cells. It happens commonly among children and resolves when the child reaches puberty. The smaller jaw size leads to difficulty in feeding infants; while in adults, micrognathia may create problem while introducing anesthesia.

Main feature of Micrognathia is an anomaly in the structure of the lower jaw as it is considerably smaller than the other parts of the face. It can be observed first during infancy. These children are difficult to feed and the jaw has a small opening. Breathing problems like apnea, dyspnea, and abnormally rapid breathing are other symptoms that are detected. The lower jaw size obstructs the airways that cause difficulty in breathing. Moreover, the tongue does not grow to an average size due to the abnormally smaller jaw size.

The causes of micrognathia are:

Pierre Robin Syndrome: It is a congenital disorder with a facial malformation. This syndrome is a genetic anomaly of chromosomes 2 and 11.

Wolf-Hirschhorn Syndrome: Wolf-Hirschhorn syndrome is caused due to depletion in chromosome 4 where distinct facial abnormalities can be noticed causing micrognathia.

Progeria as a Cause of Micrognathia: It is a rare genetic medical condition that involves rapid aging of a child and occurs as a result of genetic mutation.

Cri-du-Chat Syndrome: This genetic condition is caused because of deletion in chromosome 5. It is characterized by physical deformities, developmental disabilities, and cat-like cries.

Trisomy 13 & 18 as a Cause of Micrognathia: In both these genetic disorders, an extra genetic material is present. This extra genetic material results in severe physical deformities and mental deficiencies.

The other causes of micrognathia include the following:

• Treacher Collins syndrome
• Russell-Silver syndrome
• Turner syndrome
• Fetal alcohol syndrome
• Marfan syndrome
• Prader-Willi syndrome
• DiGeorge syndrome.

In the prenatal diagnosis, doctors may observe a small chin on the face during the ultrasound and if the doctor suspects micrognathia, will pay attention to the growth of chin during the remaining part of pregnancy. The doctor may refer the case to a specialist who can manage high-risk pregnancies. The doctor may even perform a detailed ultrasound for a closer look at the birth defects. Some doctors may even advise MRI during pregnancy to examine the baby’s palate.

Micrognathia is present at birth. It can be noticed during infancy when the child has feeding problems. This condition gets normal when the child reaches puberty as the mandible develops with the advancement of the child’s age. Treatment is generally not required for Micrognathia except a regular monitoring. Several adjustments are required to survive the feeding habit of the child with special equipment along with modified eating habits that can help to feed the child. Surgery for Micrognathia may be needed to be done by an orthodontist and braces can help to correct the misaligned teeth.

There is no direct way of preventing micrognathia and many of the underlying conditions that cause it cannot be prevented. If there is an inherited disorder, a genetic counselor may inform you whether it can pass on to your child.

Micrognathia is a congenital problem. When the lower jaw of the child grow, the feeding problem stops automatically. Corrective surgery is successful and can take 9 to 12 months to heal a child’s jaw. Treatment is not always necessary. The babies with medical conditions like Pierre Robin syndrome can live normal lives; while babies with trisomy 13 have a short life span. Doctors can tell about the outlook based on the child’s medical condition.