Dextrocardia and ventricular septal defect in the Möbius syndrome.

A case of Möbius syndrome is reported with the additional features of dextrocardia and a single ventricle, neither of which have been previously reported in the literature with this syndrome. Correlation of the period in embryogenesis of cardiac partitioning and rotation with the appearance of the cranial nuclei and limb buds would support the proposal that the fourth to the seventh week of gestation is the critical period of embryogenesis, wherein an intrauterine insult could give rise to the Möbius syndrome.