Syndrome

BASICS


DESCRIPTION


• Unilateral or bilateral facial weakness with impairment of ocular abduction


– Other cranial nerves may be involved


– Limb anomalies may be present


EPIDEMIOLOGY


Incidence


0.0002–0.002% of live births (1)


Prevalence


• Estimated 2,000 living cases worldwide (2)


• Estimated 800 living in the US (2)


RISK FACTORS


• Family history of Moebius or possibly other overlapping congenital cranial dysinnervation disorders (CCDD)


• Multiple teratogens have been suggested (1)


– Gestational hyperthermia


– Electric shock


– Chorionic villus sampling


– Abuse of benzodiazepines


– Alcohol


– Cocaine


– Thalidomide


– Misoprostol


Genetics


• Autosomal dominant, autosomal recessive and X-linked recessive have been reported.


• Variable expression and penetrance


– MBS1 (13q12.2–q13) involved in two unrelated families (1)


– MBS2 (3q21–q22) and MBS3 (10q21.3–q22.1) await confirmation (1)


– Multiple chromosomal aberrations known to have Moebius as a feature


GENERAL PREVENTION


• Avoidance of in utero exposure to known teratogens.


• Genetic counseling


PATHOPHYSIOLOGY


• Not completely understood but felt to be secondary to rhombencephalic maldevelopment involving predominantly motor nuclei and axons traversing long tracts (3)


– Complex disruption of development thought to occur between 21–34 days of embryogenesis (4)


ETIOLOGY


• Genetic/inherited


– Exposure to teratogens


COMMONLY ASSOCIATED CONDITIONS


• Crenulations on sides of tongue/hypoplasia (75%): Involvement of cranial nerve XII


• Craniofacial malformations: Epicanthal folds, flat nasal bridge, micrognathia, high arched palate, external ear defects, teeth defects, and hypertelorism (90%)


• Malformations of extremities (85%)


• Feeding problems (86%)


• Duane syndrome (34%)


• Poland syndrome (11%)


– Rare associations: Congenital heart defects, dextrocardia, arthrogryposis multiplex, urinary tract anomalies, anosmia, and hypogonadotropic hypogonadism (3)


DIAGNOSIS


HISTORY


• Family history


• Known exposure to teratogen in utero


• Other known associated anomalies


PHYSICAL EXAM


• Complete ocular examination


– Evaluate ocular motility and alignment (usually orthophoric in primary position)


– Evaluate weakness of orbicularis oculi (involvement of cranial VII)


– Evaluation of ocular surface


– Assessment of visual function


– Evaluate external structures for craniofacial findings


– Complete systemic evaluation for associated anomalies


DIAGNOSTIC TESTS & INTERPRETATION


Lab


Initial lab tests

• None required


• Consider karyotype/microarray if no teratogen is identified. Gene testing not yet available specifically for Moebius, although testing of other genes known to be causative of CCDD may have a role.


Follow-up & special considerations

Consider evaluation for mitochondrial disorder including Kearn Sayres with chronic progressive ophthalmoplegia (acquired), if history of congenital involvement unclear.


Imaging


• No imaging is necessary


– MRI of head may be performed to evaluate cranial nerves and nuclei


DIFFERENTIAL DIAGNOSIS


• Isolated cranial nerve 6 palsy


• Esotropia with pseudo-abduction deficit (especially with congenital/infantile esotropia)


• Other oromandibular limb hypogenesis syndromes: Hypoglossia-hypodactylia syndrome, Hanhart syndrome, glossopalatine ankylosis syndrome


• Chronic progressive external ophthalmoplegia and other mitochondrial disorders


• Thyroid eye disease


• Intranuclear ophthalmoplegia


TREATMENT


MEDICATION


• Ocular lubricants as needed for ocular surface drying


• Artificial tear ointment at bedtime or taping lids close may be helpful in cases of lagophthalmos


ADDITIONAL TREATMENT


General Measures


Amblyopia therapy as needed


Issues for Referral


• These patients have multiple system involvement and often need multidisciplinary approach


– Nutritionists, occupational therapist for feeding issues


– Orthopedist, physical and occupational therapist for limb anomalies


– Speech pathologist for language delay


– ENT for tracheostomy if unable to manage their secretion


– Dentist for teeth anomalies


– Neuropsychologist is often helpful


– Genetic counseling


Additional Therapies


Bandage contact lenses may be useful in the treatment of extreme corneal involvement from exposure.


COMPLEMENTARY & ALTERNATIVE THERAPIES


None proven


SURGERY/OTHER PROCEDURES


• Surgery for esotropia may be performed as needed


– Temporary tarsorrhaphy for extreme exposure may be beneficial


ONGOING CARE


FOLLOW-UP RECOMMENDATIONS


• Frequent follow-up required if ocular surface drying is present.


• As needed for amblyopia monitoring and treatment


Patient Monitoring


• Visual function and school performance


• Overall health and development of child


• Attention to concerns about self image


DIET


Adjust as needed in view of possible swallowing issues.


PATIENT EDUCATION


• Genetic counseling


• Family support network: Moebius Syndrome Foundation (www.moebiussyndrome.com)


PROGNOSIS


• Moebius is a nonprogressive congenital condition


– With good supportive care, normal life expectancy


COMPLICATIONS


• Corneal ulceration and/or perforation


• Amblyopia



REFERENCES


1. Briegel W. Neuropsychiatric findings of Mobius sequence – a review. Clin Genet 2006;70:91–97.


2. Broussard AB, Borazjani JG. The faces of Moebius syndrome: Recognition and anticipatory guidance. Am J Matern Child Nurs 2008;5:272–278.


3. Verzijl HT, van der Zwaag B, Cruysberg JR, Padberg GW. Moebius syndrome redefined: A syndrome of rhombencephalic maldevelopment. Neurology 2003;61:327–333.


4. Miller MT, Owens P, Chen F. Mobius and Mobius-like syndromes. J Pediatr Ophthalmol Strabismus 1989;26:176–189.

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Nov 9, 2016 | Posted by in OPHTHALMOLOGY | Comments Off on Syndrome
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