Möbius sequence: further in vivo support for the subclavian artery supply disruption sequence.

Möbius sequence consists of a congenital bilateral facial nerve palsy and external ophthalmoplegia often associated with malformations of the limbs and orofacial structures. The pathogenesis of the sequence is a subject of debate. However, a new hypothesis proposes that Möbius sequence results from an interruption of embryonic blood supply (subclavian artery supply disruption sequence). Here we present an infant with bilateral facial nerve palsy (VII), external ophthalmoplegia (IV, VI), paresis of cranial nerves V, IX, X, XI, and XII, absence of the pectoralis major muscle (Poland anomaly), terminal transverse limb defects, and absence of the right diaphragm. Also, he was found to have discrete foci of brainstem calcifications in the region of the dorsal respiratory group on both CT scan and the histologic sections with microscopic evidence of diffuse brainstem "injury." The anomalies and histopathology noted in this infant imply that vascular insufficiency prior to the sixth week of gestation involving the proximal sixth intersegmental artery may result in the manifestations presented in this report and lend further support for the existence of a subclavian artery supply disruption sequence.