Moebius Syndrome
Original Editor - Wendy Walker
Lead Editors
Definition/Description
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Moebius, or Möbius, syndrome is defined as congenital facial palsy combined with abnormal ocular abduction, caused by abnormal development of the 6th and 7th cranial nerves. It is a rare congenital condition that was first described by German neurologist Paul Julius Möbius in 1888[1].
Moebius syndrome is due to the loss of function of motor cranial nerves. Most cases are diagnosed during infancy. The disease is not progressive.
Clinically Relevant Anatomy
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Please see the Facial Nerve and Facial Palsy pages for information on the anatomy of the seventh cranial nerve, AKA facial nerve.
Cranial nerve six, AKA the abducens nerve, innervates the ipsilateral lateral rectus muscle which abducts the ipsilateral eye. The sixth nerve nucleus is located in the pons, just ventral to the floor of the fourth ventricle. Bilateral palsy of the abducens nerve (as seen in Moebius Syndrome) results in lack of eye movement in the horizontal plane, ie. inability to move the eyes laterally. This can be observed by testing lateral tracking of eye movement (keeping the head still) and also when the individual reads text, it is apparent that they have to move their head laterally.
Mechanism of Injury / Pathological Process
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The etiology of Moebius syndrome is not known, but it appears to be multifactorial. There has been evidence of a genetic component related to various loci on chromosomes 3, 10, and 13[2].
The close relationship embryologically between the motor nuclei of the sixth and seventh cranial nerves explains the pathology of this rare condition[3].
Clinical Presentation[edit | edit source]
Cranial Nerve VII Involvement[edit | edit source]
Bilateral facial immobility/paralysis is the most noticeable symptom, and is frequently noticed very soon after birth, with the parents reporting incomplete eyelid closure during sleep and difficulty sucking (due to lack of lip seal)[4].
However, ooccasionally the facial paralysis is not noticed for a few weeks or months, until the baby's inability to smile or the lack of facial movement with crying arouses the parents' concern. In extremely rare cases the facial paralysis is unilateral.
As the child grows, speech problems emerge due to inability to seal the lips for thee labial consonants. Speech problems are reported in 76-90% of patients with Möbius syndrome[5].
Cranial Nerve VI Involvement[edit | edit source]
Abducens nerve palsies are reported in approximately 75% of patients and are some of the most characteristic features of the syndrome.
Cranial Nerve XII Involvement[edit | edit source]
The hypoglossal nerve is the third most commonly affected cranial nerve (CN) and is involved in approximately 25% of reported cases[6]. Involvement of the hypoglossal nerves often leads to atrophy of the tongue. Patients may be unable to protrude their tongue beyond their lips because of this weakness. This involvement may result in paralysis and hypoplasia of the tongue, or fasciculations may be seen as a result of hypoglossal denervation. The ocular muscles are always involved when the tongue is affected.
Brachial Malformation [edit | edit source]
Brachial malformation is common and can involve the following:
Talipes Equinovarus AKA Clubfoot, frequently bilateral, occurs in almost one third of patients
Reports include hand malformations or congenital amputation of hand
In some cases, the affected hand is smaller than the other hand
Syndactyly is not uncommon, and brachydactyly is frequently reported
Other abnormalities in the upper extremities include finger webbing and an absence or hypoplasia of the radius, ulna, metacarpal, or phalanx
Diagnostic Procedures[edit | edit source]
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Management / Interventions
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No definitive treatment is available, with medical care being supportive and symptomatic.
Treatment for corneal ulcerations or abrasions may be required. These occur secondary to keratitis and conjunctivitis, which result from incomplete eyelid closure.
Differential Diagnosis
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Abducens (CN VI) nerve palsy
Congenital facial (CNVII) nerve palsy
Brainstem syndromes
Metabolic neuropathy
Myotonic diseases
Neuromuscular diseases
Congenital neuropathies
Congenital muscular dystrophy
Duane syndrome
Kallmann syndrome
Poland anomaly
Klippel-Feil anomaly
Key Evidence[edit | edit source]
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Resources
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Case Studies[edit | edit source]
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Recent Related Research (from Pubmed)[edit | edit source]
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References[edit | edit source]
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- ↑ Mobius PJ. Uber angeboren doppelseitige abducens-facialis-lahmung. Munchen Medizinische Wochenschrift. 1888;35:91-4.
- ↑ Uzumcu A, Karaman B, Toksoy G, Uyguner ZO, Candan S, Eris H. Molecular genetic screening of MBS1 locus on chromosome 13 for microdeletions and exclusion of FGF9, GSH1 and CDX2 as causative genes in patients with Moebius syndrome. Eur J Med Genet. Sep-Oct 2009;52(5):315-20
- ↑ May M, Schaitkin BM. Facial Nerve Disorders in Newborns and Children. In: The Facial Nerve. 2nd ed. New York, NY: Thieme New York; 2000:339-65
- ↑ Kumar D. Moebius syndrome. J Med Genet. Feb 1990;27(2):122-6
- ↑ Briegel W. Neuropsychiatric findings of Mobius sequence -- a review. Clin Genet. Aug 2006;70(2):91-7
- ↑ Kumar D. Moebius syndrome. J Med Genet. Feb 1990;27(2):122-6
