Abstract

A new family with the combination of trismus and curvature of the fingers on dorsiflexion of the wrist is described. Data from 24 affected members of this family make it likely that the measurements of mouth opening and of wrist angles are sufficient to recognize the syndrome. The affected persons also show a mild degree of short stature but only when compared with their unaffected sibs of the same sex. In the pronounced cases of trismus the coronoid process is enlarged by the extensive pull of the temporal muscle tendon unit which decreases the mandibular excursion. Surgical correction of the enlarged coronoid process may then be necessary.

The variable expressivity of this autosomal dominant trait makes it most likely that the phenotypes in the families described hitherto are due to the same mutation.