Rapp-Hodgkin syndrome (RHS) is a rare form of ectodermal dysplasia wit
h variable involvement of the hair, eyes, sweat glands, nails, and tee
th. Oral findings may include hypodontia, hypoplastic enamel, cleft li
p/palate, and a pronounced midfacial hypoplasia. The objective of this
study was to determine if the pronounced midfacial hypoplasia is the
result of a true tissue hypoplasia or displacement of midfacial tissue
s. We have identified a family in which three members, a mother and tw
o daughters, display clinical features characteristic of RHS. Clinical
and intraoral examination of these affected persons showed manifestat
ions characteristic of RHS, and several new findings were observed, in
cluding subcutaneous abscesses, palmoplantar keratosis, and keratotic
lesions located on the chest and trunk. To assess the midfacial hypopl
asia, lateral cephalometric analysis was performed on lateral headplat
es. Results of the cephalometric analysis suggest that the midfacial h
ypoplasia results from both a deficiency and a displacement of the max
illa. These findings are significant because successful dental treatme
nt of RHS relies upon accurate assessment of current and projected oro
facial development, particularly for the skeletal relations of the max
illa and mandible.