Moebius Syndrome

Moebius Syndrome

National Organization for Rare Disorders, Inc.

Important

It is possible that the main title of the report Moebius Syndrome is not the name you expected. Please check the synonyms listing to find the alternate name(s) and disorder subdivision(s) covered by this report.

Synonyms

  • congenital facial diplegia syndrome
  • congenital oculofacial paralysis
  • MBS
  • Mobius syndrome
  • Moebius sequence

Disorder Subdivisions

  • None

General Discussion

Summary

Moebius syndrome is a rare neurological disorder characterized by weakness or paralysis (palsy) of multiple cranial nerves, most often the 6th (abducens) and 7th (facial) nerves. Other cranial nerves are sometimes affected. The disorder is present at birth (congenital). If the 7th nerve is involved, the individual with Moebius syndrome is unable to smile, frown, pucker the lips, raise the eyebrows, or close the eyelids. If the 7th nerve is affected, the eye cannot turn outward past the midline. Other abnormalities include underdevelopment of the pectoral muscles and defects of the limbs. Moebius syndrome is not progressive. The exact cause is unknown. It appears to occur randomly for unknown reasons (sporadically) in most cases; however, some cases run in families suggesting that there may be a genetic component.



Introduction

Moebius syndrome is named after Paul Julius Mobius, a German neurologist, who first described the disorder in 1888. There has been disagreement in the medical literature as to a precise definition of the disorder.

Symptoms

The abnormalities and severity of Moebius syndrome can vary greatly from one person to another. Facial paralysis or weakness usually affects both sides of the face (diplegia). The 7th cranial nerve, which controls facial movements, is affected in all cases. The 6th cranial nerve, which controls eye movements, is affected in approximately 75% of cases. Less often, other cranial nerves, including the 5th, 8th, 9th, 10th, 11th, and 12th may be affected.



Infants with Moebius syndrome may drool excessively and exhibit crossed eyes (strabismus). Because the eyes do not move from side-to-side (laterally), the child is forced to turn the head to follow objects. Infants who lack facial expression and are described as having a "mask-like" face that is especially obvious when laughing or crying. Affected infants may also have difficulties feeding, including problems swallowing and poor sucking. Corneal ulceration may occur because the eyelids remain open during sleep.



There are a wide variety of additional abnormalities. Some children with Moebius syndrome have a short, malformed tongue and or an abnormally small jaw (micrognathia). Cleft palate may also be present. These abnormalities contribute to feeding and breathing difficulties. Children with cleft palate are prone to ear infections (otitis media). There may be external ear anomalies including underdevelopment of the outer portion of the ear (microtia) or total absence of the outer portion of the ear (anotia). If the 8th cranial nerve is affected, there is likely hearing loss. Dental abnormalities are not uncommon. Some affected children have difficulties with speech and delays in speech development.



Skeletal malformations can also occur including clubbed feet, underdevelopment of the lower legs, and abnormal side-to-side curvature of the spine (scoliosis). Affected individuals may also have webbing of the fingers (syndactyly), underdevelopment or absence of the fingers, and/or underdevelopment of the hand. In approximately, 15% of cases underdevelopment of the chest (pectoral) muscles and the breast on one side of the body may also occur (see Poland-Moebius syndrome in the Related Disorder section below).



Some affected children exhibit delays in attaining certain milestones such as crawling or walking, most likely due to upper body weakness; however, most children eventually catch-up. Moebius syndrome rarely is associated with minor intellectual disability. Some children have been classified as being on the autistic spectrum. The exact relationship between Moebius syndrome and autism is unknown. Some studies have suggested that autism spectrum disorders occur with greater frequency in children with Moebius syndrome; other studies have not demonstrated this and suggest that any relationship is overstated. Moebius syndrome is often associated with a variety of social and psychological consequences. The disorder can impact an individual's quality of life. The lack of facial expressions and the inability to smile can cause observers to misinterpret what an affected individual is thinking or feeling or intends. Affected individuals may avoid social situations due to anxiousness and frustration.

Causes

Most cases of Moebius syndrome occur randomly for unknown reasons (sporadically) in the absence of a family history of the disorder. In rare cases, familial patterns have been reported. Most likely, Moebius syndrome is multifactorial, which means that both genetic and environmental factors play some causative role. It is possible that in different cases there are different underlying causes (heterogeneity).



In familial cases, there is evidence that Moebius syndrome is inherited as an autosomal dominant trait. Dominant genetic disorders occur when only a single copy of an abnormal gene is necessary for the appearance of the disease. The abnormal gene can be inherited from either parent, or can be the result of a new mutation (gene change) in the affected individual. The risk of passing the abnormal gene from affected parent to offspring is 50% for each pregnancy regardless of the sex of the resulting child.



Several different theories have been proposed to explain the cause of Moebius syndrome. One hypothesis is the disorder is the result of diminished or interrupted blood flow (ischemia) to the developing fetus during pregnancy (in utero). Recent research suggests that the lack of blood affects certain areas of the lower brainstem that contain the cranial nerve nuclei. This lack of blood flow can result from an environmental, mechanical or genetic cause. Nevertheless, the underlying cause of Moebius syndrome remains inconclusive and more basic and clinical research is necessary.

Affected Populations

Moebius syndrome affects males and females in equal numbers. The disorder is present at birth (congenital). The exact incidence and prevalence rates of Moebius syndrome are unknown. One estimate places the incidence at 1 case per 50,000 live births in the United States.

Standard Therapies

Diagnosis

A diagnosis of Moebius syndrome is based upon the characteristic signs/symptoms, a detailed patient history, and a thorough clinical evaluation. There are no diagnostic tests that confirm a diagnosis of Moebius syndrome. Some specialized tests may be performed to rule out other causes of facial palsy.



Treatment

The treatment of Moebius syndrome is directed toward the specific abnormalities in each individual. Usually these children are managed by a multidisciplinary team, often in a craniofacial center. Involved specialists include: pediatricians; neurologists; plastic surgeons; ear, nose, and throat specialists (otolaryngologists); orthopedists; dental specialists; speech pathologists; specialists who assess and treat hearing problems (audiologists), specialists who treat eye abnormalities (ophthalmologists) and other healthcare professionals.



Reconstruction procedures for facial paralysis involve transfer of muscle and/or graft nerves from another area of the face or the body. An old procedure, known as temporalis tendon transfer, involves taking the temporalis muscle, one of the muscles normally used for chewing (mastication), and transferring it to the corners of the mouth. This same type of operation can be also used to improve closure of the eyelids. If the paralysis is on only one side (unilateral), a "cross-facial nerve graft" is an option. The procedure involves taking a sensory nerve from the calf, attaching it to a branch of the functioning facial nerve on the normal side of the face and then waiting until the regenerating nerve fibers cross over the face to reach the paralyzed side where it is joined to a motor nerve of a thin muscle transferred to the face by microvascular anastomosis.



The most recent procedure, called "the smile operation", involves microvascular transfer of a muscle from the thigh (gracillis) to the face and connecting the nerves that normally supply the masseter muscle (one of the muscles used for chewing). This operation has shown remarkable results in terms of speech, facial mobility and self-esteem. Frequent lubrication for dry eyes is often necessary.



Physical therapy may be needed for individuals with various orthopedic abnormalities. Occupational therapy may be beneficial, especially in patients with abnormalities of the hands, fingers and toes. Speech therapy may be necessary for some affected children. Strabismus is usually surgically correctable, although some physicians recommend delaying these procedures as the condition sometimes improves on its own with age. Operations may also be necessary for the various skeletal malformations affecting the limbs and jaws. Specialized procedures to correct abnormalities and/or underdevelopment of the chest wall and breast are available.



Splints, braces and prostheses may be necessary for individuals with congenital limb abnormalities. Genetic counseling may be of benefit for affected individuals and their families.

Investigational Therapies

Information on current clinical trials is posted on the Internet at www.clinicaltrials.gov. All studies receiving U.S. government funding, and some supported by private industry, are posted on this government web site.



For information about clinical trials being conducted at the NIH Clinical Center in Bethesda, MD, contact the NIH Patient Recruitment Office:



Toll-free: (800) 411-1222

TTY: (866) 411-1010

Email: prpl@cc.nih.gov



For information about clinical trials sponsored by private sources, in the main, contact:

www.centerwatch.com

References

TEXTBOOKS

Mulliken JB. Mobius syndrome. NORD Guide to Rare Disorders. Lippincott Williams & Wilkins. Philadelphia, PA. 2003:223-224.



Rowland LP. Ed. Merritt's Neurology. 10th ed. Lippincott Williams & Wilkins. Philadelphia, PA. 2000:602.



JOURNAL ARTICLES

Bogart KR, Tickle-Degnen L, Joffe MS. Social interaction experiences of adults with Moebius syndrome: a focus group. J Health Psychol. 2012;[Epub ahead of print]. http://www.ncbi.nlm.nih.gov/pubmed/22257565



Magli A, Bonavolonta P, Forte R, Vassallo P. Lower eyelid surgery for lagophthalmos in Mobius and Poland-Mobius syndromes. J Craniofac Surg. 2011;22:e53-e54. http://www.ncbi.nlm.nih.gov/pubmed/22134324



Briegel W, Schimek M, Kamp-Becker I. Moebius sequence and autism spectrum disorders – less frequently associated than formerly thought. Res Dev Disabil. 2010;31:1462-1466. http://www.ncbi.nlm.nih.gov/pubmed/20621443



Rankin JK, Andrews C, Chan WM, Engle EC. HOXA1 mutations are not a common cause of Mobius syndrome. J AAPOS. 2010;14:78-80. http://www.ncbi.nlm.nih.gov/pubmed/20227628



Byrne P, Kim M, Boahene K, Millar J, Moe K. Temporalis tendon transfer as part of a comprehensive approach to facial reanimation. Arch Facial Plast Surg. 2007;9:234-241. http://www.ncbi.nlm.nih.gov/pubmed/17638756



Briegel W. Neuropsychiatric findings of Mobius sequence - review. Clin Genet. 2006;70:91-97. http://www.ncbi.nlm.nih.gov/pubmed/16879188



Verzijl HT, Padberg GW, Zwarts MJ. The spectrum of Mobius syndrome: an electrophysiological study. Brain. 2005;128:1728-1736. http://www.ncbi.nlm.nih.gov/pubmed/15829555



Verzijl HT, van der Zwagg B, Cruysberg JR, Padberg GW. Mobius syndrome redefined: a syndrome of rhombencephalic maldevelopment. Neurology. 2003;61:327-333. http://www.ncbi.nlm.nih.gov/pubmed/12913192



INTERNET

McKusick VA., ed. Online Mendelian Inheritance in Man (OMIM). Baltimore. MD: The Johns Hopkins University; Entry No:1157900; Last Update:02/01/2011. Available at: http://omim.org/entry/157900 Accessed on: June 26, 2012.



Redett RJ. A Guide to Understanding Moebius Syndrome. Children's Craniofacial Association. 2006. Available at: http://www.ccakids.com/Syndrome/Moebius.pdf Accessed On: June 26, 2012



Palmer CA. Mobius Syndrome. Emedicine Journal, June 14 2006. Available at: http://emedicine.medscape.com/article/1180822-overview Accessed on: June 26, 2012.

Resources

Children's Craniofacial Association

13140 Coit Road

Suite 517

Dallas, TX 75240

USA

Tel: (214)570-9099

Fax: (214)570-8811

Tel: (800)535-3643

Email: contactCCA@ccakids.com

Internet: http://www.ccakids.com



March of Dimes Birth Defects Foundation

1275 Mamaroneck Avenue

White Plains, NY 10605

Tel: (914)997-4488

Fax: (914)997-4763

Tel: (888)663-4637

Email: Askus@marchofdimes.com

Internet: http://www.marchofdimes.com



FACES: The National Craniofacial Association

PO Box 11082

Chattanooga, TN 37401

Tel: (423)266-1632

Fax: (423)267-3124

Tel: (800)332-2373

Email: faces@faces-cranio.org

Internet: http://www.faces-cranio.org



Let's Face It

University of Michigan, School of Dentistry / Dentistry Library

1011 N. University

Ann Arbor, MI 48109-1078

USA

Tel: (360)676-7325

Email: faceit@umich.edu

Internet: http://www.dent.umich.edu/faceit



AmeriFace

P.O. Box 751112

Limekiln, PA 19535

USA

Tel: (702)769-9264

Fax: (702)341-5351

Tel: (888)486-1209

Email: info@ameriface.org

Internet: http://www.ameriface.org



Moebius Syndrome Foundation

PO Box 147

Pilot Grove, MO 65276

USA

Tel: (660)834-3406

Fax: (660)834-3407

Email: vicki@moebiussyndrome.com

Internet: http://www.moebiussyndrome.com



Cleft Palate Foundation

1504 East Franklin Street

Suite 102

Chapel Hill, NC 27514-2820

USA

Tel: (919)933-9044

Fax: (919)933-9604

Tel: (800)242-5338

Email: info@cleftline.org

Internet: http://www.cleftline.org



NIH/National Institute of Neurological Disorders and Stroke

P.O. Box 5801

Bethesda, MD 20824

Tel: (301)496-5751

Fax: (301)402-2186

Tel: (800)352-9424

TDD: (301)468-5981

Internet: http://www.ninds.nih.gov/



National Foundation for Facial Reconstruction

333 East 30th Street, Lobby Unit

New York, NY 10016

Tel: (212)263-6656

Fax: (212)263-7534

Internet: http://www.nffr.org



Birth Defect Research for Children, Inc.

976 Lake Baldwin Lane

Orlando, FL 32814

USA

Tel: (407)895-0802

Email: staff@birthdefects.org

Internet: http://www.birthdefects.org



Genetic and Rare Diseases (GARD) Information Center

PO Box 8126

Gaithersburg, MD 20898-8126

Tel: (301)251-4925

Fax: (301)251-4911

Tel: (888)205-2311

TDD: (888)205-3223

Internet: http://rarediseases.info.nih.gov/GARD/



Madisons Foundation

PO Box 241956

Los Angeles, CA 90024

Tel: (310)264-0826

Fax: (310)264-4766

Email: getinfo@madisonsfoundation.org

Internet: http://www.madisonsfoundation.org



Let Them Hear Foundation

1900 University Avenue, Suite 101

East Palo Alto, CA 94303

Tel: (650)462-3174

Fax: (650)462-3144

Email: info@letthemhear.org

Internet: http://www.letthemhear.org



For a Complete Report

This is an abstract of a report from the National Organization for Rare Disorders, Inc.® (NORD). Cigna members can access the complete report by logging into myCigna.com. For non-Cigna members, a copy of the complete report can be obtained for a small fee by visiting the NORD website. The complete report contains additional information including symptoms, causes, affected population, related disorders, standard and investigational treatments (if available), and references from medical literature. For a full-text version of this topic, see http://www.rarediseases.org/search/rdblist.html.

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