Radiologic evidence for absence of the facial nerve in Möbius syndrome.
OBJECTIVE
To detail the radiologic findings in Möbius syndrome, in order to clarify its pathogenetic mechanisms.


METHODS
High resolution three-dimensional T1 (MP rage) and T2 (CISS) weighted MRI were used to study the cisternal and canalicular portion of the seventh cranial nerve in six Möbius patients. Also, the anteroposterior dimension of the brainstem was measured at the level of the pons in the authors' 6 patients and in 20 age-matched healthy control subjects. Furthermore, the MRIs were evaluated for associated congenital brain anomalies.


RESULTS
The facial nerves were absent in all six patients despite residual function in some facial muscles. The authors confirmed brainstem hypoplasia but did not find tegmental calcifications. The anteroposterior dimension of the brainstem ranged between 17 and 25 mm vs 20 to 27 mm for controls. In three patients there were congenital abnormalities in the posterior fossa.


CONCLUSIONS
The absent facial nerves on MRI and the unusual distribution of the facial weakness, which is characteristic of Möbius syndrome, suggests that other cranial nerves, possibly the trigeminal, hypoglossal, or glossopharyngeal nerve, aberrantly innervate some lower facial muscles. Radiologic findings support the notion that Möbius syndrome is part of a more complex congenital anomaly of the fossa posterior.
Verzijl
Harriëtte T F M
HT
Department of Neurology, University Medical Center Nijmegen, PO Box 9101, 6500 HB Nijmegen, The Netherlands. h.verzijl@neuro.umcn.nl
Valk
Jaap
J
de Vries
Rob
R
Padberg
George W
GW
D000328:Adult; D001933:Brain Stem / Q000002:abnormalities*; D002648:Child; D003391:Cranial Nerves / Q000002:abnormalities; D019465:Craniofacial Abnormalities / Q000150:complications / Q000473:pathology; D002658:Developmental Disabilities / Q000209:etiology / Q000473:pathology / Q000503:physiopathology; D005152:Facial Muscles / Q000294:innervation / Q000473:pathology / Q000503:physiopathology; D005154:Facial Nerve / Q000002:abnormalities*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D020331:Mobius Syndrome / Q000473:pathology* / Q000503:physiopathology; D018908:Muscle Weakness / Q000209:etiology / Q000503:physiopathology; D009421:Nervous System Malformations / Q000473:pathology* / Q000503:physiopathology; D009473:Neuronal Plasticity / Q000502:physiology; D015835:Ocular Motility Disorders / Q000209:etiology / Q000503:physiopathology; D013131:Spine / Q000002:abnormalities; D014059:Tongue / Q000294:innervation / Q000503:physiopathology; D014060:Tongue Diseases / Q000209:etiology / Q000503:physiopathology