Moebius syndrome is a congenital condition in which several nerves or muscles in the head are non-functional or only partly functional. First identified in the late 19th century, it has been documented in only about 300 cases in the English-speaking world since then. The cause is unknown, but some theories suggest either genetic or blood flow problems resulting in nerve or muscle dysfunction. Moebius syndrome is associated with other congenital malformations, such as club foot, and between thirty and forty percent of patients with Moebius syndrome also suffer from autism. Diagnosis is almost always made near the time of birth and there may be miscarriage or early infant death as a result of difficulty breathing and ingesting food.
Several different nerves may be involved in Moebius syndrome, but the facial nerves always are. The main visible effect is slackness of facial expression in the patient, and Moebius syndrome may be first noticed when a newborn fails to learn how to smile and does not change facial expressions when crying. Should the child survive into adulthood, social interaction may be difficult because the patient is unable to express their feelings and attitudes through facial expression.
More specific nerves that are implicated are those governing the eyelids and eyes. Patients with Moebius syndrome generally cannot close their eyes completely when sleeping, although they may blink. There is also often impairment in being able to look at the extremes of side to side or up and down.
Another important implication of the facial nerves is mouth slackness. Patients with Moebius syndrome have difficulty closing their mouths, and the upper lip is often excessively prominent. Partly because of the syndrome, and partly because it is associated with congenitally small jaw structures, Moebius syndrome causes difficulty in chewing and swallowing food. In many cases food gets trapped between the patient’s cheek and gums. Suckling in infants is often impaired and the inability to suckle may be one major cause of infant death among Moebius syndrome patients.
Moebius syndrome is not progressive and is not contagious, and has only a small hereditary component. Although the patient may appear to have subnormal intelligence, and some do, in most cases a patient with Moebius syndrome is no less smart than other people, just less able to show it. If a child with Moebius syndrome survives into adulthood, she will most likely live a normal lifespan.
Sources:
http://emedicine.medscape.com/article/1180822-overview
http://www.moebiussyndrome.com/
http://www.ninds.nih.gov/disorders/mobius/moebius.htm
