Identification of DSPP novel variants and phenotype analysis in dentinogenesis dysplasia Shields type II patients

ObjectivesTo investigate the genetic causes and teeth characteristics of dentin dysplasia Shields type II(DD-II) in three Chinese families.Materials and methodsData from three Chinese families affected with DD-II were collected. Whole-exome sequencing (WES) and whole-genome sequencing (WGS) were conducted to screen for variations, and Sanger sequencing was used to verify mutation sites. The physical and chemical characteristics of the affected teeth including tooth structure, hardness, mineral content, and ultrastructure were investigated.ResultsA novel frameshift deletion mutation c.1871_1874del(p.Ser624fs) in DSPP was found in families A and B, while no pathogenic mutation was found in family C. The affected teeth's pulp cavities were obliterated, and the root canals were smaller than normal teeth and irregularly distributed comprising a network. The patients' teeth also had reduced dentin hardness and highly irregular dentinal tubules. The Mg content of the teeth was significantly lower than that of the controls, but the Na content was obviously higher than that of the controls.ConclusionsA novel frameshift deletion mutation, c.1871_1874del (p.Ser624fs), in the DPP region of the DSPP gene causes DD-II. The DD-II teeth demonstrated compromised mechanical properties and changed ultrastructure, suggesting an impaired function of DPP. Our findings expand the mutational spectrum of the DSPP gene and strengthen the understanding of clinical phenotypes related to the frameshift deletion in the DPP region of the DSPP gene.

Automated summary

This study investigated the genetic causes and teeth characteristics of dentin dysplasia Shields type II(DD-II) in three Chinese families. Whole-exome sequencing (WES) and whole-genome sequencing (WGS) were used to identify variations, and Sanger sequencing was conducted to verify mutation sites. A frameshift deletion mutation in DSPP gene was found in two families, while no pathogenic mutation was found in one family. The affected teeth showed abnormal tooth structure, reduced hardness, and irregular dentinal tubules, along with altered mineral content. This study expands the understanding of the genetic basis and phenotypic characteristics of DD-II.