The vascular theory of embryopathogenesis for Mobius syndrome is proposed in a case report of a 3-month-old boy from the University of New Mexico School of Medicine, Albuquerque, NM. At birth, he had bilateral facial and abducens palsies, left acheiria (congenital absence of the hand), and transposition of the aorta and pulmonary artery. He was lethargic, cyanotic, and in respiratory distress, and he expired after an arterial switch procedure with closure of a septal defect. The authors cite 2 reports of Mobius syndrome with cardiac anomalies, both presenting with dextrocardia and the Poland anomaly (unilateral hypoplasia or absence of pectoral muscles, nipple, and upper limb). An intrapartum insult during the fourth to seventh week of gestation is consistent with the vascular theory of embryopathogenesis. 
COMMENT. Congenital facial diplegia and abducens palsy, Mobius syndrome, has been explained as either a primary hypoplasia of cranial nerve nuclei or a primary deficiency of the muscles derived from the first two branchial arches. A dysgenesis of both neural and muscular tissue has been proposed in some cases. In the above case report, the concomitant occurrence of the vascular anomaly supports the theory of impaired cranial nerve nuclear development due to interruption of vascular supply at or around the sixth intrauterine week.