Last updated: 11/24/2009

Otosclerosis affects about 10% of the United States population. It is an autosomal dominant disorder with variable penetrance. These terms mean that a child having one parent with otosclerosis has a 50% chance of inheriting the gene for the disorder,...

but that not everyone who has the gene will develop otosclerosis. In addition, some researchers think that the onset of the disorder is triggered when a person who has the gene for otosclerosis is infected with the measles virus. This hypothesis is supported by the finding that the incidence of otosclerosis has been steadily declining in countries with widespread measles vaccination.

Otosclerosis develops most frequently in people between the ages of 10 and 30. In most cases, both ears are affected; however, about 10–15% of patients diagnosed with otosclerosis have loss of hearing in only one ear. The disorder affects women more frequently than men by a ratio of 2:1. Pregnancy is a risk factor for onset or worsening of otosclerosis.

With regard to race, Caucasian and Asian Americans are more likely to develop otosclerosis than African Americans.