Congenital unilateral multiple cranial neuropathy: an etiology shared with Mobius syndrome?

Mobius syndrome was originally described as bilateral 6th and 7th cranial nerve palsy and has since been expanded to include involvement of nearly all cranial nerves, limb deformities, orofacial anomalies and deficits in intellectual function. The etiology of Mobius syndrome remains elusive. Here we present a case with unilateral 5th, 7th, 9th, 10th and 12th cranial nerve palsy along with MRI evidence of ipsilateral brainstem hypoplasia. We propose the unilateral pathology supports the theory that vascular malformation in utero, which can be due to various etiologies, leads to brainstem ischemia and is the key factor in development of Mobius syndrome.