“…Though mono-or polyostotic fibrous dysplasia, as well as precocious puberty or skin pigmentation, are more often isolated, it is evident that the association of two or three of these anomalies, to which eventually are added other lesions, is so frequent as to imply a lesion that often affects some dis¬ tinct segments of the ecto-and mesoderm.2, 6,9 Knaggsll has considered the factor of heredity in the lesion of the connective tis¬ sue cell of the embryo, as well as the incidence of environmental factors. In a re¬ view of statistics covering 40 cases, Bickel and associates12 found that osteogenesis imperfecta was hereditary in 27.5%.…”