Möbius syndrome

Möbius syndrome is a rare congenital neurological disorder which is characterized by facial paralysis and the inability to move the eyes from side to side. Most people with Möbius syndrome are born with complete facial paralysis and cannot close their eyes or form facial expressions. Limb and chest wall abnormalities sometimes occur with the syndrome. People with Möbius syndrome have normal intelligence, although their lack of facial expression is sometimes incorrectly taken to be due to dullness or unfriendliness. It is named for Paul Julius Möbius, a German neurologist who first described the syndrome in 1888. In 1994, the "Moebius Syndrome Foundation" was founded, and later that year the first "Moebius Syndrome Foundation Conference" was held in Los Angeles. A charity for Möbius syndrome was set up and registered in the UK in 1999 by Linda Anderson from Tyne and Wear, whose son had been born with the condition in 1980. She campaigned for many years, held conferences and gave medical speeches in America before she had to step away from the charity because of ill health.

Signs and symptoms

People with Möbius syndrome are born with facial paralysis and the inability to move their eyes laterally. Often, their upper lip is retracted due to muscle shrinkage. Occasionally, the cranial nerves V and VIII are affected. If cranial nerve VIII is affected, the person experiences hearing loss.

Other symptoms that sometimes occur with Möbius syndrome are:
* Limb abnormalities—clubbed feet, missing fingers or toes
* Chest-wall abnormalities ( Poland syndrome)
* Crossed eyes ( strabismus)
* Difficulty in breathing and/or in swallowing
* Corneal erosion resulting from difficulty in blinking

Children with Möbius syndrome may have delayed speech because of paralysis of muscles that move the lips, soft palate and tongue root. However, with speech therapy, most people with Möbius syndrome can develop understandable speech. Möbius syndrome has been associated with increased occurrence of the symptoms of autism. Some children with Möbius syndrome are mistakenly labeled as intellectually disabled because of their expressionless faces, strabismus and frequent drooling.

Social and lifestyle effects

Möbius syndrome does not prevent individuals from experiencing personal and professional success. Due to the importance of facial expression and smiling in social interaction, the inability to form either can lead to individuals with Möbius being perceived as unhappy, unfriendly or uninterested in conversations. Individuals who are familiar with Möbius patients such as family or friends can recognize other signals of emotion such as body language, to the point that they sometimes report forgetting that the person has facial paralysis. Indeed, people with Möbius syndrome are often adept at compensating for a lack of expression by using body language, posture, and vocal tone to convey emotion.

Pathogenesis

Möbius syndrome results from the underdevelopment of the VI and VII cranial nerves. The VI cranial nerve controls lateral eye movement, and the VII cranial nerve controls facial expression.

The causes of Möbius syndrome are poorly understood. It is thought to result from a vascular disruption (temporary loss of bloodflow) in the brain during prenatal development. There can be many reasons for vascular disruption leading to Möbius syndrome. Most cases do not appear to be genetic. However, genetic links have been found in a few families. Some maternal trauma may result in impaired or interrupted blood flow (ischemia) or lack of oxygen (hypoxia) to a developing fetus. Some cases are associated with reciprocal translocation between chromosomes or maternal illness. In the majority of cases of Möbius syndrome in which autosomal dominant inheritance is suspected, sixth and seventh cranial nerve paralysis (palsy) occurs without associated limb abnormalities.

The use of drugs and a traumatic pregnancy may also be linked to the development of Möbius syndrome. The use of the drugs misoprostol or thalidomide by women during pregnancy has been linked to the development of Möbius syndrome in some cases. Misoprostol is used to induce abortions in Brazil and Argentina as well as in the United States. Misoprostol abortions are successful 90% of the time, meaning that 10% of the time the pregnancy continues. Studies show that the use of misoprostal during pregnancy increases the risk of developing Möbius syndrome by a factor of 30. While this is a dramatic increase in risk, the incidence of Möbius syndrome without misoprostal use is estimated at one in 50000 to 100000 births (making the incidence of Möbius syndrome with misoprostol use, less than one in 1000 births). The use of cocaine (which also has vascular effects) has been implicated in Möbius syndrome.

Some researchers have suggested that the underlying problem of this disorder could be congenital hypoplasia

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