Otological manifestations of a new familial polyostotic bone disorder. Fifty members of a family with a unique autosomal dominant bone disease were investigated. Nineteen of the family members were either known to have, or were strongly suspected of having the disease. All but one of these had a hearing loss which was conductive in the younger age group and mixed in the older members. The common finding in those who had middle ear surgery was replacement of the long process of incus by a fibrous band. The histological features were similar to those found in Paget's disease. The age of onset, distribution of lesions and radiographic findings, however, were not typical of this disorder. 