Purpose: Möbius syndrome is characterized by abducens and facial nerve palsy. However, the presence/absence of corresponding cranial nerves on MRI was not fully evaluated. The purpose of this study was to investigate the mechanism of Möbius syndrome by associating the presence of abducens and facial nerves on MR imagings with clinical features.
Methods: We retrospectively reviewed the medical records and MR imagings of nine patients with Möbius syndrome between January 2004 and October 2015. The presence/absence of abducens and facial nerves on MR imaging, as well as corresponding neuro-ophthalmologic clinical features, was investigated.
Results: Facial palsy was bilateral in six and unilateral in three patients. Abduction was limited bilaterally in five and unilaterally in four patients. The degrees of facial palsy and abduction limitation were variable, and asymmetric even in the bilateral cases. MR imaging documented bilateral absence of the abducens and facial nerves in six, absence of unilateral facial nerve and bilateral abducens nerves in one, and absence of facial and abducens nerves unilaterally on the same side in another. Both abducens and facial nerves were visualized bilaterally only in the one remaining patient.
Conclusions: The absence of abducens and facial nerves on MR imaging was mostly correlated with the findings of facial palsy and abduction limitation in patients with Möbius syndrome. MR imaging aids in diagnosis of Möbius syndrome by documenting the absence or presence of abducens and facial nerves.
Keywords: Abducens nerve; Facial nerve; MR imaging; Möbius syndrome.