Otosclerosis.

Otosclerosis is one of the more common forms of adult-onset hearing loss with a prevalence of 0.3-0.4% in Caucasians. It is typically characterized by a conductive hearing loss due to labyrinthine endochondral sclerosis that upon stapedio-vestibular joint invasion results in loss of free motion of the stapes. Its etiology remains poorly understood with both environmental factors and genetic causes implicated in its development. Several environmental influences have been studied and numerous genomic loci have been mapped in families segregating autosomal-dominant otosclerosis. Population-based studies have also identified associations with several genes. These advances are improving our understanding of this complex disease.