Dentin Sialophosphoprotein: The DSPP gene provides instructions for making a protein called dentin sialophosphoprotein.
1. Normal Function
Soon after it is produced, this protein is cut into two smaller proteins: dentin sialoprotein and dentin phosphoprotein. These proteins are components of dentin, which is a bone-like substance that makes up the protective middle layer of each tooth. A third smaller protein produced from dentin sialophosphoprotein, called dentin glycoprotein, was identified in pigs but has not been found in humans.
Although the exact functions of the DSPP-derived proteins are unknown, these proteins appear to be essential for normal tooth development. Dentin phosphoprotein is thought to be involved in the normal hardening of collagen, the most abundant protein in dentin. Specifically, dentin phosphoprotein may play a role in the deposition of mineral crystals among collagen fibers (mineralization).
The DSPP gene is also active in the inner ear, although it is unclear whether it plays a role in normal hearing.
2. Health Conditions Related to Genetic Changes
2.1 Dentinogenesis Imperfecta
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.
2.2 Nonsyndromic Hearing Loss
3. Other Names for This Gene
The entry is from https://medlineplus.gov/genetics/gene/dspp
- Beattie ML, Kim JW, Gong SG, Murdoch-Kinch CA, Simmer JP, Hu JC. Phenotypicvariation in dentinogenesis imperfecta/dentin dysplasia linked to 4q21. J DentRes. 2006 Apr;85(4):329-33.
- Dong J, Gu T, Jeffords L, MacDougall M. Dentin phosphoprotein compoundmutation in dentin sialophosphoprotein causes dentinogenesis imperfecta type III.Am J Med Genet A. 2005 Jan 30;132A(3):305-9.
- Kim JW, Hu JC, Lee JI, Moon SK, Kim YJ, Jang KT, Lee SH, Kim CC, Hahn SH,Simmer JP. Mutational hot spot in the DSPP gene causing dentinogenesis imperfectatype II. Hum Genet. 2005 Feb;116(3):186-91.
- Kim JW, Nam SH, Jang KT, Lee SH, Kim CC, Hahn SH, Hu JC, Simmer JP. A novelsplice acceptor mutation in the DSPP gene causing dentinogenesis imperfecta type II. Hum Genet. 2004 Aug;115(3):248-54.
- MacDougall M, Dong J, Acevedo AC. Molecular basis of human dentin diseases. AmJ Med Genet A. 2006 Dec 1;140(23):2536-46. Review.
- Malmgren B, Lindskog S, Elgadi A, Norgren S. Clinical, histopathologic, andgenetic investigation in two large families with dentinogenesis imperfecta typeII. Hum Genet. 2004 Apr;114(5):491-8.
- McKnight DA, Simmer JP, Hart PS, Hart TC, Fisher LW. Overlapping DSPPmutations cause dentin dysplasia and dentinogenesis imperfecta. J Dent Res. 2008 Dec;87(12):1108-11. Erratum in: J Dent Res. 2009 Jan;88(1):95.
- McKnight DA, Suzanne Hart P, Hart TC, Hartsfield JK, Wilson A, Wright JT,Fisher LW. A comprehensive analysis of normal variation and disease-causingmutations in the human DSPP gene. Hum Mutat. 2008 Dec;29(12):1392-404. doi:10.1002/humu.20783.
- Song Y, Wang C, Peng B, Ye X, Zhao G, Fan M, Fu Q, Bian Z. Phenotypes andgenotypes in 2 DGI families with different DSPP mutations. Oral Surg Oral MedOral Pathol Oral Radiol Endod. 2006 Sep;102(3):360-74.
- Song YL, Wang CN, Fan MW, Su B, Bian Z. Dentin phosphoprotein frameshiftmutations in hereditary dentin disorders and their variation patterns in normalhuman population. J Med Genet. 2008 Jul;45(7):457-64. doi:10.1136/jmg.2007.056911.
- Xiao S, Yu C, Chou X, Yuan W, Wang Y, Bu L, Fu G, Qian M, Yang J, Shi Y, Hu L,Han B, Wang Z, Huang W, Liu J, Chen Z, Zhao G, Kong X. Dentinogenesis imperfecta 1 with or without progressive hearing loss is associated with distinct mutations in DSPP. Nat Genet. 2001 Feb;27(2):201-4. Erratum in: Nat Genet 2001Mar;27(3):345.
- Yamakoshi Y, Hu JC, Fukae M, Iwata T, Kim JW, Zhang H, Simmer JP. Porcinedentin sialoprotein is a proteoglycan with glycosaminoglycan chains containingchondroitin 6-sulfate. J Biol Chem. 2005 Jan 14;280(2):1552-60.
- Yamakoshi Y, Hu JC, Fukae M, Zhang H, Simmer JP. Dentin glycoprotein: theprotein in the middle of the dentin sialophosphoprotein chimera. J Biol Chem.2005 Apr 29;280(17):17472-9.
- Yamakoshi Y, Hu JC, Iwata T, Kobayashi K, Fukae M, Simmer JP. Dentinsialophosphoprotein is processed by MMP-2 and MMP-20 in vitro and in vivo. J BiolChem. 2006 Dec 15;281(50):38235-43.
- Zhang X, Zhao J, Li C, Gao S, Qiu C, Liu P, Wu G, Qiang B, Lo WH, Shen Y. DSPPmutation in dentinogenesis imperfecta Shields type II. Nat Genet. 2001Feb;27(2):151-2.