Nuclear agenesis: Möbius' syndrome: the congenital facial diplegia syndrome.

Thus Harlan (1881) described the appearance of a patient with bilateral congenital facial and external rectus paralysis. Chisholm's account (1882) was equally clear. The collation of cases of congenital facial palsy combined with other cranial muscle weakness by Mobius (1892) led to more general recognition of nuclear degeneration (as he termed it), or agenesis, and to eponymous fame. More recently Henderson (1939) and Danis (1945) have fully reviewed the condition. Paralysis may be total or partial, unilateral or bilateral. The face is practically always involved, the external rectus muscles rather commonly, those supplied by the twelfth, third and fifth nerves, and the palate, may be affected. The weakness or paralysis is assumed to be due to aplasia of the appropriate nuclei, but the pathological evidence is hard to interpret, and until it becomes decisive, ideas about the nature of the condition must depend partly on consideration of how the various cranial paralyses come to be associated. Further weight must be attached to the circumstantial evidence provided by other congenital anomalies found in these patients. Most of them have been seen and recorded in adolescence and adult life, but patients seen in early childhood may show additional features, for example, mandibular hypoplasia and laryngeal stridor, which do not appear in other lists such as Wilson's (1940): epicanthus, absence of lacrymal caruncles, microphthalmia, deformed ears, syndactyly, micromely, localized muscle defects and club foot. The following account includes all the cases that I have seen. Those with solitary unilateral facial paralysis are omitted, for in them the common presence of deformity of the face and external ear suggests that simple pressure by the shoulder may have produced the deformation ofadjacent structures during intra-uterine life (Browne, 1936). Case 1. Unilateral Extel Recta and Facial Pals C.P., a boy, was born in 1948. He was the second child of healthy parents not related by blood: there was no illnss during pregnancy; he was born by normal labour, at term, and weighed 6 lb. Right facial weakness was noticed at once: he could not suck well but was breast fed for two months. Because gain in weight was slow he was brought to hospital at 3 months. Weakness of the right external rectus muscle was noted. At 5 months there was slight hypoplasia of the right side of the face, which was completely paralysed. At 9 months there was a right convergent squint, which was treated operatively when he was 23 months old.