Acromelic frontonasal dysostosis.

We report on 3 male and 2 female infants with acromelic frontonasal dysostosis. All 5 had a frontonasal malformation of the face and nasal clefting associated with striking symmetrical preaxial polysyndactyly of the feet and variable tibial hypoplasia. In contrast, the upper limbs were normal. This rare variant of frontonasal dysplasia may represent a distinct autosomal-recessive disorder. We suggest that the molecular basis of this condition may be a perturbation of the Sonic Hedgehog (SHH) signalling pathway, which plays an important part in the development of the midline central nervous system/craniofacial region and the limbs.