ABSTRACT
Objective To report a familial dentinogenesis imperfecta type Ⅱ (DGI type Ⅱ) with a novel splicing mutation in DSPP (dentin sialophosphoprotein) gene.Methods Based on the result of linkage analysis performed previously to map the candidate gene DSPP in the family, the promoter,the first four exons and exon-intron boundaries of DSPP were directly sequenced for the members of the DGI type Ⅱ family. Denaturing high performance liquid chromatography (DHPLC) analysis was performed to confirm the results of sequencing.Results A novel splicing mutation of 23 bp deletion in intron 2 of DSPP gene was identified by DNA sequence analysis. The mutation changed acceptor site sequence from CAG to AAG, and might result in functional abolition of possible branch point site in intron 2. DHPLC result was consistent with that of sequencing. The mutation may be identified in all affected individuals, but not found in normal members of the family and 50 controls.Conclusion These results suggest the deleted mutation of DSPP gene causes DGI type Ⅱ in the family. The mutation has not been reported before.