Introduction
THREE different etiological factors are, as a rule, considered responsible for the development of otosclerosis: constitutional, local, and general.The constitutional factor accounts for the heredity of the disease. The mode of inheritance is most probably a mono-hybrid autosomal dominant inheritance with a penetrance of the pathological gene of between 25% and 40%.1The local factors bringing about the exclusive involvement of the labyrinthine capsule and the characteristic distribution of the otosclerotic foci within the latter are considered to be of a developmental, circulatory, or mechanical nature. Their discussion would go beyond the scope of this paper.Among the general activating factors, metabolic disturbances must be considered in the first place. However, no abnormalities were found in the lipoprotein,2 calcium, phosphorus, cholesterol, or protein content of the blood serum,3 including the distribution of serum haptoglobins, the isoenzyme activity of serum esterase, and acid and alkaline phophatase