Moebius syndrome is present at birth, and its first sign is often the infant’s difficulty with sucking. The disease affects the cranial nerves, preventing normal facial muscle movement, which affects facial expression and eye movement. There are a variety of signs and symptoms of Moebius disorder and a great deal of potential variation from one patient to another.
Infants with Moebius syndrome also commonly have incomplete closure of the eyelid when sleeping, excessive drooling, crossed eyes, and inability to smile on a normal developmental schedule.
Children and adults with Moebius syndrome exhibit a masklike facial appearance with no ability to express emotions. Other common facial symptoms and features are an inability to close the mouth and prominence of the upper lip. Between 76% and 90% of patients with Moebius syndrome have speech difficulties. Corneal ulcers are common because the eyelids cannot close properly during sleep.
Cleft palate is a common symptom, as well as external ear anomalies. If the 8th cranial nerve is affected, hearing loss is possible. Dental abnormalities such as misaligned teeth and childhood cavities may occur. Speech delays are common.
A small chin and small mouth are common signs of Moebius syndrome, as well as an abnormally shaped tongue. There may be a cleft palate or unusually high and arched palate.
Cognitive Symptoms
Most people with Moebius syndrome have normal intelligence, but approximately 10% to 15% have mild mental retardation. Moebius syndrome is associated with autism. Some studies have estimated a prevalence of about 30% to 40% among children with the disorder. The relationship between autism and Moebius syndrome is not well understood.
In children, developmental delays are common, although they usually catch up in time.
Skeletal Symptoms
More than half of children with Moebius syndrome have malformation of the limbs, such as clubbed feet and underdeveloped lower legs. Upper extremities may show webbed fingers, absence of fingers, or underdeveloped hands. Some patients experience scoliosis or underdevelopment of chest muscles.
Developmental Symptoms
Loss of ability to move the eyes impacts development that can lead to significant cognitive impairment. Without the ability to locate objects by moving the eyes, information about spatial orientation of objects is disconnected from recognition of those objects.
Primary motor symptoms observed in people with Moebius syndrome include:
- Hypotonia
- Musculo-skeletal dysmorphism
- Delay in righting oneself (problems with balance)
- Delay in walking
- Clumsiness
Language problems like dyslalia and disorders of phonological coding, speech structure, and writing are also frequent. Visual problems include difficulties with scanning and exploration.
Moebius syndrome also leads to secondary problems like oral-motor deficits and inability to categorize facial expressions.
Emotional and Psychological Symptoms
Lack of facial expressions and feeding challenges can interfere with normal mother-child bonding. As well, children may grow up being misunderstood, taunted or isolated by other children and adults due to their lack of facial expression. People may assume that these children have deficits such as mental retardation and autism because of the masklike face. People with Moebius syndrome are therefore vulnerable to anxiety and depression. Children and adults with Moebius syndrome may benefit from counseling to build self-esteem, learning coping skills, and learning how to advocate for themselves with others who make incorrect assumptions.
References
- https://rarediseases.org/rare-diseases/moebius-syndrome/
- https://ijponline.biomedcentral.com/articles/10.1186/s13052-016-0256-5
Further Reading