Infantile cortical hyperostosis.

The genetic aspects of infantile cortical hyperostosis are discussed. A pedigree is presented, based on the history and clinical and radiological investigations of all living members of the family, with data from 11 cases with the condition in two generations, and one possible case from a third generation. The data suggest that an autosomal dominant gene with varying expressivity could be responsible in this family and, though the genetic outlook is unfavourable, it is fully balanced by the benign character of the disease. A chronic form of infantile cortical hyperostosis affecting 2 girls and 1 boy in the family is described with a follow-up of 3 to 5 years. There was no deterioration in the general state of health of the patients and no abnormality was detected in laboratory investigations. At the end of the second year of life, curving of the long bones was usually present radiologically and the appositionless corticalis was paper thin with extended marrow cavity. With increasing age the bowing of the bones became less noticeable (but can be permanent in some cases), the corticalis thickened, while marrow cavity volume decreased. In the marrow cavities the remains of insufficiently resorbed original hyperostoses were seen. All the affected bones exhibited both numerous Park's stress lines and osteoporosis, more marked in the bones of the lower extremities. Even these changes disappeared with increasing age. Neither the metaphyses nor epiphyseal ossification centres were affected by the condition.