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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 Paralysis (also known as plegia) is a loss of motor function in one or more muscles. Paralysis can also be accompanied by a loss of feeling (sensory loss) in the affected area if there is sensory damage. In the United States, roughly 1 in 50 ...
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 Paul Julius Möbius (January 24, 1853 – January 8, 1907) was a German neurologist born in Leipzig. His grandfather was German mathematician and theoretical astronomer, August Ferdinand Möbius (1790–1868). Prior to entering the medical field ...
, 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 8 (eight) is the natural number following 7 and preceding 9. In mathematics 8 is: * a composite number, its proper divisors being , , and . It is twice 4 or four times 2. * a power of two, being 2 (two cubed), and is the first number of t ...
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 Clubfoot is a birth defect where one or both feet are supinated, rotated inward and plantar flexion, downward. Congenital clubfoot is the most common congenital malformation of the foot with an incidence of 1 per 1000 births. In approximately ...
, missing fingers or toes * Chest-wall abnormalities ( Poland syndrome) * Crossed eyes ( strabismus) * Difficulty in breathing and/or in swallowing *
Corneal erosion Recurrent corneal erosion is a disorder of the human eye, eyes characterized by the failure of the cornea's outermost layer of epithelial cells to attach to the underlying basement membrane (Bowman's layer). The condition is excruciatingly painful ...
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 The autism spectrum, often referred to as just autism or in the context of a professional diagnosis autism spectrum disorder (ASD) or autism spectrum condition (ASC), is a neurodevelopmental condition (or conditions) characterized by difficulti ...
. 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 Ischemia or ischaemia is a restriction in blood supply to any tissue, muscle group, or organ of the body, causing a shortage of oxygen that is needed for cellular metabolism (to keep tissue alive). Ischemia is generally caused by problems wi ...
) or lack of oxygen (
hypoxia Hypoxia means a lower than normal level of oxygen, and may refer to: Reduced or insufficient oxygen * Hypoxia (environmental), abnormally low oxygen content of the specific environment * Hypoxia (medical), abnormally low level of oxygen in the tis ...
) 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 A drug is any chemical substance that causes a change in an organism's physiology or psychology when consumed. Drugs are typically distinguished from food and substances that provide nutritional support. Consumption of drugs can be via inhalat ...
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 Hypoplasia (from Ancient Greek ὑπo- ''hypo-'' 'under' + πλάσις ''plasis'' 'formation'; adjective form ''hypoplastic'') is underdevelopment or incomplete development of a tissue or organ.agenesis of the cranial nerve nuclei. Certain symptoms associated with Möbius syndrome may be caused by incomplete development of facial nerves, other cranial nerves, and other parts of the central nervous system.


Oral/dental concerns


Neonatal

When a child is born with Möbius syndrome, there may be difficulty in closing the mouth or swallowing. The tongue may fasciculate (quiver) or be hypotonic (low muscle tone). The tongue may be larger or smaller than average. There may be low tone of the muscles of the soft palate, pharynx, and the masticatory system. The palate may be arched excessively (a high palate), because the tongue does not form a suction that would normally shape the palate down further. The palate may have a groove (this may be partially due to intubation early on if it is for an extended period of time) or may be cleft (incompletely formed). The opening to the mouth may be small. Feeding problems may become a critical issue early on if adequate nutrition is difficult.


Primary dentition

The
primary Primary or primaries may refer to: Arts, entertainment, and media Music Groups and labels * Primary (band), from Australia * Primary (musician), hip hop musician and record producer from South Korea * Primary Music, Israeli record label Works * ...
(baby) teeth generally start coming in by 6 months of age, and all 20 teeth may be in by two and a half years of age. The eruption timing varies greatly. There may be an incomplete formation of the enamel on the teeth (enamel
hypoplasia Hypoplasia (from Ancient Greek ὑπo- ''hypo-'' 'under' + πλάσις ''plasis'' 'formation'; adjective form ''hypoplastic'') is underdevelopment or incomplete development of a tissue or organ.micrognathia Micrognathism is a condition where the jaw is undersized. It is also sometimes called mandibular hypoplasia. It is common in infants, but is usually self-corrected during growth, due to the jaws' increasing in size. It may be a cause of abnorma ...
or retrognathia). The front teeth may not touch when the child closes down because the back teeth have overerrupted or because of incomplete formation of the maxilla. This condition is called an anterior open bite and has facial/skeletal implications. The saliva may be thick, or the infant may have a dry mouth.


Transitional dentition

Between age 5 and 7, most children start losing their primary teeth. Occasionally, some primary teeth are slow to exfoliate (fall out), and the dentist may want to remove a primary tooth early to prevent orthodontic problems. Likewise, premature loss of primary teeth may create orthodontic problems later on. When a tooth is lost prematurely, removable or fixed spacers may be needed to prevent the shifting of teeth. Interceptive orthodontic treatment can be initiated at this stage of development to help with crowding or to help relate the upper and lower jaws. Consistent with a high palate is a narrow arch shape of the upper teeth as they line up in the mouth. This may cause the upper front teeth to flare out and become more prone to fracture if accidentally hit. Interceptive orthodontics has an important role in this situation. Appliances that expand the upper arch tend to bring the front teeth back into a more-normal position. Some appliances can even help allow the front teeth to close to normal in an open-bite situation. The mouth and lips may tend to get dry with the Möbius patient. Lack of a good oral seal (lips together) allows the gingiva (gums) to get dry and may get inflamed and irritated.


Permanent dentition

After the last primary tooth is lost, usually around the age of twelve, final orthodontic treatment can be initiated. A patient that has not been able to close or swallow well probably will have an open bite, deficient lower-jaw growth, a narrow archform with crowded teeth, and upper anterior flaring of teeth. Orthognathic (jaw) surgery may be indicated. This should be completed in most situations before the smile surgery where the gracilis muscle is grafted to the face. Genetic links to 13q12.2 and 1p22 have been suggested.


Diagnosis

Diagnosis is typically made by the physical characteristics and symptoms, patient history and a thorough clinical evaluation. There is no specific diagnostic test that confirms Möbius syndrome. Some specialised tests may be carried out to rule out other causes of facial palsy.


Treatment

There is no single course of medical treatment or cure for Möbius syndrome. Treatment is supportive and in accordance with symptoms. If they have difficulty nursing, infants may require feeding tubes or special bottles to maintain sufficient nutrition. Physical, occupational, and speech therapy can improve motor skills and coordination and can lead to better control of speaking and eating abilities. Often, frequent lubrication with eye drops is sufficient to combat dry eye that results from impaired blinking. Surgery can correct crossed eyes, protect the cornea via
tarsorraphy Tarsorrhaphy is a surgical procedure in which the eyelids are partially sewn together to narrow the eyelid opening. It may be done to protect the cornea in cases of corneal exposure, as a treatment for Graves' ophthalmopathy, Möbius syndrome or a ...
, and improve limb and jaw deformities. Sometimes called smile surgery by the media, muscle transfers grafted from the thigh to the corners of the mouth can be performed to provide the ability to smile. Although "smile surgery" may provide the ability to smile, the procedure is complex and can take twelve hours for each side of the face. Also, the surgery cannot be considered a "cure" for Möbius syndrome, because it does not improve the ability to form other facial expressions.


Epidemiology

It is estimated that there are, on average, 2 to 20 cases of Möbius syndrome per million births. Although its rarity often leads to late diagnosis, infants with this disorder can be identified at birth by a "mask-like" lack of expression that is detectable during crying or laughing and by an inability to suck while nursing because of paresis (palsy) of the sixth and seventh cranial nerves. Also, because a person with Möbius syndrome cannot follow objects by moving their eyes from side to side, they turn their head instead.


Society and culture

Literature and media with mentions of Möbius syndrome include: * The protagonist of the novel ''Painted'' by Eliza Wyatt and Christian Leffler has Möbius syndrome. * In the second season of '' Scream Queens'', Daira Janessen (
Riley McKenna Weinstein Riley may refer to: Names * Riley (given name) * Riley (surname) Places * Riley Park–Little Mountain, a neighborhood in Vancouver, British Columbia, Canada * Riley Creek (Ontario), a tributary of the Black River in Central Ontario, Canada * Rile ...
), also known as Chanel 8, has Möbius syndrome. * In the first season of American medical drama '' The Good Doctor'', a teenage patient is depicted with Möbius syndrome. * In the BBC TV series ''Face'', Loraine Deveney, a Möbius syndrome patient, was portrayed as a successful example of "smile surgery" performed by R. M. Zuker, M.D. * The German TV series '' Dr. Stefan Frank'' episode "Ein himmlisches Lächeln" (season 4, episode 4) is about a young boy living with Möbius syndrome. * The book "Secret Weapon" of the Alex Rider series gives a mention to Darcus Drake, a man with Möbius syndrome. * In “The Adventure of the Man Who Never Laughed”, a story written by John H. Watson, M.D./discovered by J. N. Williamson, and collected in ''Holmes For The Holidays'', edited by Martin H. Greenberg, Jon L. Lellenberg and Carol-Lynn Waugh (Berkley Prime Crime, 1996), a missing person has Möbius syndrome. * In the sixteenth season of '' Grey's Anatomy'', a patient presents with Möbius syndrome.


References


External links

*
Möbius syndrome
at the
National Institute of Neurological Disorders and Stroke The National Institute of Neurological Disorders and Stroke (NINDS) is a part of the U.S. National Institutes of Health (NIH). It conducts and funds research on brain and nervous system disorders and has a budget of just over US$2.03 billion. The ...
{{DEFAULTSORT:Mobius Syndrome Neurological disorders Syndromes affecting the eye Genetic disorders with OMIM but no gene Rare syndromes Syndromes affecting the nervous system