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Mutational hot spot in the DSPP gene causing dentinogenesis imperfecta type II
Jung-Wook Kim1, Jan C-C Hu, Jae-Il Lee
1Department of Biological and Material Sciences, University of Michigan Dental Research Lab, 1210 Eisenhower Place, Ann Arbor, MI 48108, USA.
Human Genetics
|December 14, 2004
Summary
A single DSPP gene mutation causes both dentinogenesis imperfecta (DGI) types II and III. This finding suggests these are phenotypic variations of one disorder, not separate diseases.
Area of Science:
- Genetics
- Oral Biology
- Biochemistry
Background:
- Current classification of hereditary dentin defects includes dentin dysplasia (DD) and dentinogenesis imperfecta (DGI).
- The distinction between DGI type II and DGI type III phenotypes remains debated.
- Advances in genetic research have illuminated the etiologies of inherited dentin disorders.
Purpose of the Study:
- To investigate the genetic basis of DGI type II and type III.
- To determine if DGI type II and DGI type III represent distinct phenotypes or variations of a single condition.
- To propose a revised classification for hereditary dentin defects.
Main Methods:
- Genetic analysis of affected individuals from Korean and Caucasian families.
- Identification and characterization of mutations in the DSPP gene.
- Correlation of identified mutations with clinical and radiographic phenotypes.
Main Results:
- A specific mutation (c.52G-->T, p.V18F) in the DSPP gene was identified in both families.
- This mutation, previously linked to DGI type II, was found to cause phenotypes consistent with both DGI type II and DGI type III.
- The DSPP gene mutation site appears to be a mutational hot spot.
Conclusions:
- DGI type II and DGI type III are not distinct diseases but phenotypic variations of a single inherited disorder.
- A single DSPP gene mutation can manifest as either DGI type II or DGI type III.
- The classification system for hereditary dentin defects should be modified to reflect this finding, potentially using the term 'hereditary opalescent dentin' or 'DGI type II' for both phenotypes.