Clinical otosclerosis, the single most common cause of hearing impairment, is characterized by isolated endochondral bone sclerosis of the labyrinthine capsule. Otosclerotic foci invade the stapediovestibular joint (oval window) and interfere with free motion of the stapes. Mean ... Clinical otosclerosis, the single most common cause of hearing impairment, is characterized by isolated endochondral bone sclerosis of the labyrinthine capsule. Otosclerotic foci invade the stapediovestibular joint (oval window) and interfere with free motion of the stapes. Mean age of onset is in the third decade and 90% of affected persons are under 50 years of age at the time of diagnosis. Approximately 10% of affected persons develop profound sensorineural hearing loss across all frequencies (summary by Tomek et al., 1998). - Genetic Heterogeneity of Otosclerosis The locus associated with otosclerosis-1 (OTSC1) has been mapped to chromosome 15q26.1. Other loci associated with otosclerosis include OTSC2 (605727) on chromosome 7q; OTSC3 (608244) on chromosome 6p; OTSC4 (611571) on chromosome 16q; OTSC5 (608787) on chromosome 3q22-q24; OTSC7 (611572) on chromosome 6q13; OTSC8 (612096) on chromosome 9p13.1-q21.11; and OTSC10 (615589) on chromosome 1q41-q44. The symbols OTSC6 and OTSC9 were reserved by the HUGO Gene Nomenclature Committee on January 30, 2003 and February 10, 2009, respectively, for as yet unpublished loci for otosclerosis.
Reports of familial conductive hearing loss can be traced back at least to Toynbee (1841). The term 'otosclerosis' was introduced by Politzer (1903), who defined it as a 'disease that has its seat in the labyrinthine capsule [and] ... Reports of familial conductive hearing loss can be traced back at least to Toynbee (1841). The term 'otosclerosis' was introduced by Politzer (1903), who defined it as a 'disease that has its seat in the labyrinthine capsule [and] leads, through new formation and growth of osseous tissue, to ankylosis of the stapes in the fenestra ovalis.' Deafness interpreted as otosclerosis and beginning as early as age 5 years in some cases was described by Kabat (1943) in 19 members of 4 generations of a family.
In a case-control study of 206 Caucasians with otosclerosis and 282 Caucasian controls, Chen et al. (2007) identified 2 haplotypes composed of 5 SNPs in the COL1A1 gene (see 120150.0051) that were ... - Associations Pending Confirmation In a case-control study of 206 Caucasians with otosclerosis and 282 Caucasian controls, Chen et al. (2007) identified 2 haplotypes composed of 5 SNPs in the COL1A1 gene (see 120150.0051) that were significantly associated with otosclerosis: a protective H2 haplotype and a susceptibility H3 haplotype. The authors concluded that these regulatory SNPs have a very mild effect on susceptibility to otosclerosis.
Clinical otosclerosis has a prevalence of 0.2 to 1% among white adults (cited by Tomek et al., 1998). Otosclerosis is said to be rare in Japan (Shimizu, 1965).