Otosclerosis: a local manifestation of a generalized connective tissue disorder?

The hypothesis that otosclerosis is a local manifestation of a clinically and genetically heterogeneous group of generalized connective tissue disorders was tested by quantitative biochemical techniques. In contrast to previous studies, no significant differences were found in individual glycosaminoglycans excreted in urine of control subjects and patients with otosclerosis. Moreover, no significant differences were detected in the rate of synthesis and secretion of glycosaminoglycans and collagen in skin fibroblast cultures of patients and controls. Preliminary results obtained with more sensitive and specific methods suggest a possible error in collagen metabolism. Polyacrylamide gel electrophoresis revealed slight differences in migration patterns of several collagenous proteins between patients and control subjects. In addition, collagenase was significantly increased in three of five patients.