Möbius syndrome due to brain stem tegmental necrosis.

Möbius syndrome undoubtedly results from a variety of disorders affecting central or peripheral portions of appropriate cranial nerves or their target muscles. Pathological alterations observed in cranial nuclei are most often viewed as aplastic or dysplastic lesions. Two patients with Möbius syndrome with associated facial and skeletal malformations showed mineralized necrotic foci in multiple brain stem nuclei. Prenatal encephalomalacic lesions represent the pathological basis for some cases of congenital static Möbius syndrome.