Moebius syndrome

What is Moebius syndrome?

Moebius syndrome is a congenital condition, meaning it is present at birth, in which certain nerves within the face do not work. People affected cannot move the muscles of their face to form expressions and cannot move their eyes to the outside. As a result, they have a relatively expressionless, ‘mask-like’ face, and they turn their head to look at objects rather than moving their eyes.

In-depth look

Although the exact figure is not known, Moebius syndrome is likely to be found in about one in 100,000 children. The cause for Moebius syndrome is also not well understood, but it is thought to be due to a temporary disruption in the blood supply to part of the brain during development as an embryo.

As a result of this disruption, the parts of the brain that controls the affected nerves do not develop as they should, and the child is unable to use these nerves. What causes this blood supply disruption is not clear, but it appears that there are certain drugs, such as cocaine, that, if used in pregnancy, increase the likelihood of developing the condition. Moebius syndrome is named after Paul Julius Möbius, a German Neurologist, who described the condition in 1888.

The main nerves affected in Moebius syndrome are the facial nerve, also known as cranial nerve 7, which controls the muscles of the face, except those used in chewing, and the abducens nerve, also known as cranial nerve 6.

Missing the facial nerve means that the affected person will not be able to raise their eyebrows, smile, frown or create other facial expressions. It also means that they may not be able to close their eyes fully, resulting in dry or irritated eyes, or that they may have difficulties keeping liquids inside their mouth, potentially causing them to drool as a result. There is often difficulty producing all the sounds necessary for clear speech, although most people with Moebius syndrome develop understandable speech after speech therapy.

The lack of the abducens nerve means that the eyes cannot turn toward the outside, although they can turn toward the inside and can look up and down. As a result, both eyes may not be looking in the same direction, and people with Moebius syndrome often overcome their inability to turn their eye by looking forward and moving their head, although maintaining eye contact is often difficult.

Moebius syndrome is often the only problem affecting people with this condition but it can be seen in conjunction with other conditions such as Poland syndrome and autistic behavior. In addition to the two main nerves affected, it can also affect other nerves such as those that control chewing, enable hearing or control swallowing.

Children with Moebius syndrome often also have a small lower jaw compared to the upper and a small tongue. They also tend to hold their mouth in a slightly opened position. Because of the change in muscle activity around and inside the mouth, dental development can be affected, and pediatric dentistry and pediatric craniofacial orthodontics are usually required.

It can affect children throughout their life not only in terms of the physical problems described above but also because of psychosocial issues. People with Moebius syndrome generally have normal intelligence, but are often considered to have a lower intelligence due to the lack of facial expression. Because of this lack of expression, they can be incorrectly judged to be disinterested or unfriendly in social settings. They often compensate for this with body language.

Moebius syndrome is a static condition, in that it doesn’t generally improve or worsen over time. Since there is no cure for the condition, treatment is concentrated on improving the features of patients with Moebius syndrome.

What are the signs and symptoms of Moebius syndrome?

Signs to look for are a lack of facial expressions, the inability to look to the side and difficulty with feeding.

How is Moebius syndrome diagnosed?

Moebius syndrome is diagnosed by a careful clinical assessment and detailed physical examination of the nerves themselves, complications arising from the lack of nerve activity and other frequently associated conditions.

How is Moebius syndrome treated?

There is no cure for Moebius syndrome, so treatment is planned to give people with this condition the best quality of life and the lowest psychosocial concerns. This is best done in the context of a multidisciplinary craniofacial team.

Feeding - At or shortly after birth, the child may need help with feeding. Most children cope well with adapted bottles to help overcome the difficulty in developing suction in the mouth, but if this unsuccessful, then a tube may need to be passed into the stomach to help with feeding.

Ophthalmology (eye) - The lack of the facial nerve means that the eye often does not close fully, so the surface of the eyes are likely to need protection using eye drops and eye ointment, often assisted by taping the eyes closed at night. Regular pediatric ophthalmology review is essential to provide the best care for the eyes.

• Eye surgery - When the child is older, an operation may be recommended to insert a gold weight into the upper eyelid to help it to close by gravity, protecting the eye without the need for eye medication or taping.

Plastic surgery - Many children find the inability to smile a significant psychosocial problem and seek help in improving this. There are several operations to help produce a smile, and these often involve using either one of the muscles normally used for chewing to create a smile or placing a muscle from the inner thigh under the skin of the cheek and connecting it to one of the working nerves in the face. This procedure often provides the best outcome in terms of the quality of the smile, but it is an operation that takes most of the day and requires several days’ recovery period in the hospital. It will also need to be repeated to treat the other side.

• Eyebrow surgery - Other operations for Moebius syndrome are usually small procedures to treat particular concerns raised by the patient. These often include raising the eyebrows if they are starting to droop or tightening the lower lip and corner of the mouth if there is difficulty keeping fluids or food in the mouth.

Aftercare and a continued relationship between the patient and the craniofacial team is important in Moebius syndrome.

These individual members of the craniofacial team all have a part to play:

• Speech pathologists will help with feeding shortly after birth and provide speech therapy to help make speech understandable.

• Developmental psychologists monitor the development of the child and arrange services as necessary to help the child learn

• Pediatric ophthalmologists treat the eyes and keep them working well despite the lack of protection.

• Pediatric dentists - pediatric craniofacial orthodontists and pediatric oral and maxillofacial surgeons monitor and treat the teeth over time

• Pediatric social workers ensure that the child and family are receiving the services that they need for this complex condition.

• Pediatric plastic surgeons undertake the operations described above.