Möbius syndrome

Diagnosing Möbius syndrome

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Möbius syndrome is a rare neurological condition, present from birth, in which the muscles that control facial expressions and eye movement are weak or paralyzed. Affected individuals cannot express emotion with their faces; for example, they cannot smile when they are happy, or frown when they are angry. There are also other problems coming from this weakness or paralysis, such as feeding difficulties. 
The name Möbius syndrome comes from the German neurologist Möbius, who described the condition at the end of the 19th century. It is also known as congenital facial diplegia, or congenital ophthalmoplegia and facial paresis.

Presentation of Möbius syndrome

The injury can affect the facial muscles and the ocular muscle on one side or on both sides, and to varying degrees. Other cranial nerves may be affected as well, usually the nerve that controls the tongue muscles, but both the nerve that controls swallowing and the one that controls chewing muscles may also be impacted. Some children are born with a cleft palate, which requires specific measures and surgery. Regarding the different kinds of muscle paralysis that occur, the consequences include not only impact on the ocular muscles, but also impaired facial motor control and facial expressions, as well as impaired oral motor control, affecting the person’s ability to speak and articulate.

In a Swedish hospital/habilitation based study, comprising 25 individuals, almost half had congenital skeletal malformations in their upper and/or lower extremities. There are also cases of congenital malformations of hands, e.g. ones where the person’s fingers grow together. Patients may also suffer from a condition named Poland syndrome, which involves under-developed thoracic muscles in combination with congenital hand malformation. In cases of congenital malformation of the lower extremities, the patient may also have congenital toe malformations as well as so-called clubfoot.

The symptomatic presentation varies greatly between different individuals with Möbius syndrome, firstly based on the degree and type of cranial nerve impact and if there are any concurrent congenital malformations of extremities, and secondly depending on whether any cognitive disorders and mental retardation are present. Most affected individuals with Möbius syndrome, however, have normal intelligence.

Because it also affects the muscles that control eye-movement, it can be difficult for individuals suffering from Möbius syndrome to make eye contact; it can also be difficult for them to follow movement with their eyes, or to keep their eyes facing the same direction resulting in strabismus. It can even be difficult for them to blink or completely close their eyes, which can lead to eye irritation or dryness.

How common is Möbius syndrome?

As of yet there are no population-based studies concerning prevalence of Möbius syndrome or what the prevalence rate for various associated problems are, but it has been estimated that the condition affects approximately between 1 in 50,000 to 1 in 500,000 newborns.

Alternative and additional diagnoses

Because of the presence of eye contact difficulties and other communication difficulties that are present in Möbius syndrome, there has been some controversy as to whether Möbius syndrome is associated with Autism Spectrum Disorder.

What causes Möbius syndrome?

The cause of Möbius syndrome is unknown, but it is most probably the result of a combination between genetic and environmental factors. So far, no specific gene mutation or any other genetic cause has been identified, although some research seems to indicate changes in specific regions of chromosome 3, 10 or 13 in some families. Certain drugs taken during pregnancy also seem to increase the risk of Möbius syndrome. There are studies that indicate that the injuries and symptoms present in cases of Möbius syndrome, are the result of disruptions of the blood circulation on the brain stem level, during early pregnancy between weeks 4 and 8.

Treatment and follow up of Möbius syndrome

Examination, treatment and follow-up of individuals with Möbius syndrome must be planned individually, based on the symptomatic presentation at hand. Many cases need multi-professional examination, treatment and follow-up within healthcare and habilitation services.

Other tools available for Möbius syndrome

There are several patient support and advocacy resources with for example the Moebius syndrome foundation: https://moebiussyndrome.org/