Five cases of DeMyer sequence: an interophthalmic dysplasia

Five cases with vomero-septal-prolabium agenesis, four with premaxillary agenesis, and one with hemipremaxillary agenesis are presented. All five patients had complete clefts of the secondary palate. No known family history for craniofacial dysmorphia was reported. Height and weight ranged from 2nd to 10th centile. Psychological testing showed intelligent quotients of 121, 93, 72 for three patients; two were microcephalic with undetermined IQ, but severe generalized developmental delay. CT scans for the patient with the IQ of 72 and for one of the two microcephalic subjects showed normal brain structures. The other microcephalic patients had midline prosencephalic dysgenesis. Cephalometric analysis of the cranial base and interorbital dimension using normal standards and self indexing showed hypotelorism and small anterior cranial bases to be apparently related to reduced size of the sphenoid. An intact ethmoid, nasal bone, and crista galli appear to represent key anatomic differences in these patients as compared to classical holoprosencephaly sequence subjects. It was suggested that this pattern of midline facial agenesis may range from a solitary central incisor to the most severe variant presented. Using the embryologic classification, these subjects fall best under the heading of craniofacial dysplasia rather than cerebral craniofacial dysplasia, as a different type of interophthalmic dysplasia or DeMyer sequence.