- A second gene for otosclerosis, OTSC2, maps to chromosome 7q34-36. Van Den Bogaert, K., Govaerts, P.J., Schatteman, I., Brown, M.R., Caethoven, G., Offeciers, F.E., Somers, T., Declau, F., Coucke, P., Van de Heyning, P., Smith, R.J., Van Camp, G. Am. J. Hum. Genet. (2001)