DSPP

More than 20 mutations in the DSPP gene have been identified in people with dentinogenesis imperfecta. These genetic changes are responsible for two forms of this disorder, type II and type III. Mutations in this gene also cause dentin dysplasia type II, a disorder with signs and symptoms very similar to those of dentinogenesis imperfecta. However, dentin dysplasia type II affects the primary (baby) teeth much more than the permanent teeth. Some researchers believe that this type of dentin dysplasia and dentinogenesis imperfecta types II and III are actually forms of a single disorder.

About half of DSPP gene mutations affect dentin sialoprotein, altering its transport in cells. The remaining mutations affect dentin phosphoprotein, interfering with its normal production and/or secretion. As a result of these abnormalities of DSPP-related proteins, teeth have abnormally soft dentin. Teeth with defective dentin are discolored, weak, and prone to breakage and decay.

Although the DSPP gene is active in the inner ear, it is unclear whether DSPP gene mutations are related to the hearing loss found in a few older individuals with dentinogenesis imperfecta type II.

MedlinePlus Genetics provides information about Nonsyndromic hearing loss