Brachy/ectrodactyly and absence or hypoplasia of the fibula: an autosomal dominant condition with low penetrance and variable expressivity.

A complex dysostosis characterized by brachy- and/or ectrodactyly and fibular hypoplasia was found in two distantly related individuals. The proposita, aged 25 years, showed metacarpal and phalangeal hypoplasia on both hands, ectrodactyly on both feet, and nearly complete bilateral absence of the fibula. Only milder acromelic defects were detected in a second cousin. A similar pattern of skeletal involvement had been previously described in an unrelated Italian family. The peculiar segregation pattern can be explained by autosomal dominant inheritance with low penetrance and variable expressivity.