A cephalometric study of the craniofacial skeleton in trichorhinophalangeal syndrome.

A prominent feature of the trichorhinophalangeal syndrome is a very characteristic facies. This study quantitates differences in craniofacial skeleton between affected and unaffected members of the same kindred. Standard scores for various measurements taken from lateral cephalometric radiographs were compared for statistical significance, and these were further correlated with similar data calculated from length measurements of the middle phalanx of the second digit. The affected group had a shortened posterior face height (p less than 0.01) associated with a short mandibular ramus (p less than 0.01) as well as a reduced and superiorly deflected posterior cranial base (p less than 0.01). These craniofacial changes result in a steep inclination of the lower border of the mandible (p less than 0.01) and suggest disturbances in the epiphyseal growth sites of the skull as demonstrated by a high degree of correlation between the dysplasia of the cranial base, shortening of the posterior portion of the face, and shortening of the middle phalanx of the second digit.