Otosclerosis is an early-middle adult life genetic disease affecting bone remodelling in the ear. Current knowledge of otosclerosis as an inherited disease dates to the mid-19th century, and we report here an attempt to understand the genetics of otosclerosis and detect its heterogeneity. The analysis was conducted on 151 otosclerotic families. The results of our study indicate that while heredity plays an important role in the manifestation of the disease a substantial portion of otosclerotic cases could arise due to non-genetic causes.