Otosclerosis and TGF-[beta]1 gene in black South Africans.

Otosclerosis is a spongifying disease of the labyrinthine capsuleof unknown aetiology that occurs only in humans. (1,2) It affects thetemporal bone, a focus of bone resorption and reactive bone formationdeveloping into otospongiotic weak bone. (1,2) The prevalence ofclinical otosclerosis is 0.3-0.4% in adult Caucasians (2) and is lowamong Japanese, Chinese, Indonesians and American Indians, (3) while thecondition is extremely rare in blacks. (1,3,4) It is one of the mostcommon causes of progressive conductive hearing loss among adultCaucasians. (4) Theories about the aetiology of otosclerosis have beenpostulated but, despite extensive research, its origin remains unclear.(1)