Other facial features which distinguish it from Apert's are a more retruded appearance to the forehead, more severe proptosis, normal orientation of the palpebral fissures, and a more normal appearance of the mouth. Crouzon's follows an autosomal dominant mode of transmission. Pfeiffer's disease is also a close relative of Apert's syndrome, although is less severe. It is characterized by acrocephaly, broad thumbs and great toes and partial soft tissue syndactyly of the hands. It also follows an autosomal dominant mode of transmission.
Most cases are familial, but sporadic cases exist.
Saethre-Chotzen syndrome has a more variable presentation. The most consistent features of this syndrome include acrocephaly, hypertelorism, nasal septal deviation, lid ptosis, and mild syndactyly of the hands and feet. Saethre-Chotzen is possibly the most common of all the craniosynostosis syndromes. Despite its commonness, however, the syndrome is probably underdiagnosed. This is due ot the great variability in expression even within affected families, as well as the relative mildness of the abnormalities.