Möbius syndrome with oculomotor nerve paralysis without abducens paralysis.

Möbius syndrome is typified by bilateral facial nerve palsies, usually with abducens palsies. We examined an infant with Möbius syndrome who had bifacial weakness and third nerve palsies, but intact abduction of both eyes. Lower cranial nerve involvement, leading to respiratory, swallowing, and cardiac difficulties, was also present. Pathologic examination of the brainstem showed absent or hypoplastic third, seventh, tenth, and twelfth nerve nuclei. The fourth, fifth, sixth, and eighth nerve nuclei were intact. In Möbius syndrome with ocular motor palsies, rarely the sixth nerve may be spared.