Too much bone: the middle ear in sclerosing bone dysplasias.

The middle ear changes in Sclerosteosis and Van Buchem disease are described. Reduced bone resorption occurs due to faulty activity of the sclerostin molecule, a product of the recently discovered SOST gene in chromosome 17. Syndactyly draws attention to scleroteosis, and a conductive hearing loss develops before age six in both conditions. Acute, repeated attacks of facial palsy, similar to Bell's palsy, are usually the first symptoms in both conditions. Total facial nerve decompression can stop the attacks of facial paralysis. The hearing loss is a problem because new bone formation continues up to age 21. Life saving craniectomy becomes necessary when increased intracranial pressure develops, and this may have to repeated. The sclerostin molecule is now of major interest to the researchers who want to develop a treatment for osteoporosis.