The rare syndrome of hereditary cleidocranial dysostosis is characterized by defective ossification of the clavicles and the membranous bones of the cranium. The first case was reported by Morand, in 1766, and the second by Barlow,1 in 1883. It was not until 1898, however, that the affection was brought into prominence by Marie and Sainton,2 who described the condition under the name of hereditary cleidocranial dysostosis. In 1905, Villaret and Francoz3 reported an instance of a woman and her three children who were all affected, and compiled forty-one additional cases from the literature. Fitzwilliams,4 in 1910, observed two cases, and compiled and analyzed fifty-eight others. Langmead,5 in 1916, reported the occurrence of eighteen cases in four generations, and observed seven of them.
In the family forming the basis of this communication, nine cases have occurred in three generations. Five of these subjects have been observed