IADR Abstract Archives
Whole-Exome Sequencing Identifies CSGalNAcT-1 Mutations as Cause of Dentin Dysplasia
Objectives: Dentin Dysplasia (DD) is a rare dentin abnormality affecting both primary and permanent dentitions. Genetic mutations associated with DD are not fully understood. The goal of this study was to investigate genetic mutations associated with Dentin Dysplasia Type II (DD-II) in a Caucasian family using whole-exome sequencing.
Methods: A Caucasian family with DD-II phenotype was recruited. Clinical and radiographic examinations were performed and documented. Blood samples from an affected 12-year-old male patient and four family members were collected for genomic DNA isolation. Exome sequencing was performed to identify genetic variants. PCR for specific primers were designed to further confirm exome sequencing results. Gene expression pattern was evaluated during mouse tooth development using immunohistochemistry and confocal microscopy. Knock-in and knock-down assays were used to determine the mutation functions on its target gene expressions in dental cells by RT-PCR and Western blotting analyses.
Results: The patient presents with a normal colored permanent dentition with thistle-tube shaped pulp chamber, pulp stones, and obliterated pulp cavities. Whole-exome sequencing revealed a heterozygous nonsense mutation of Chondroitin Sulfate N-Acetylgalactosaminyltransferase-1 (CSGalNAcT-1) (p. Tyr224*/c.672T>G) in the proband, which was neither present in any Single Nucleotide Polymorphism databases, nor in 30 health controls in our study. Expression pattern of CSGalNACT-1 was co-expressed with its substrate chondroitin sulfate (CS), dentin sialophosphoprotein (DSPP) and dentin matrix protein 1 (DMP1) in odontoblasts and dentin of mouse teeth. shRNAs of CSGalNACT-1 down-regulated this gene expression while overexpression of CSGalNACT-1 up-regulated this gene expression in mouse dental mesenchymal cells, therefore resulting in alteration of its target gene expression.
Conclusions: We, for the first time, observed that CSGalNAcT-1 mutation is associated with DD-II using whole-exome sequencing. Co-expression of this gene and its substrates was present in odontoblasts and dentin, providing biological plausibility for mutations in CSGalNAcT-1 underlying the pathogenesis of DD-II.
Methods: A Caucasian family with DD-II phenotype was recruited. Clinical and radiographic examinations were performed and documented. Blood samples from an affected 12-year-old male patient and four family members were collected for genomic DNA isolation. Exome sequencing was performed to identify genetic variants. PCR for specific primers were designed to further confirm exome sequencing results. Gene expression pattern was evaluated during mouse tooth development using immunohistochemistry and confocal microscopy. Knock-in and knock-down assays were used to determine the mutation functions on its target gene expressions in dental cells by RT-PCR and Western blotting analyses.
Results: The patient presents with a normal colored permanent dentition with thistle-tube shaped pulp chamber, pulp stones, and obliterated pulp cavities. Whole-exome sequencing revealed a heterozygous nonsense mutation of Chondroitin Sulfate N-Acetylgalactosaminyltransferase-1 (CSGalNAcT-1) (p. Tyr224*/c.672T>G) in the proband, which was neither present in any Single Nucleotide Polymorphism databases, nor in 30 health controls in our study. Expression pattern of CSGalNACT-1 was co-expressed with its substrate chondroitin sulfate (CS), dentin sialophosphoprotein (DSPP) and dentin matrix protein 1 (DMP1) in odontoblasts and dentin of mouse teeth. shRNAs of CSGalNACT-1 down-regulated this gene expression while overexpression of CSGalNACT-1 up-regulated this gene expression in mouse dental mesenchymal cells, therefore resulting in alteration of its target gene expression.
Conclusions: We, for the first time, observed that CSGalNAcT-1 mutation is associated with DD-II using whole-exome sequencing. Co-expression of this gene and its substrates was present in odontoblasts and dentin, providing biological plausibility for mutations in CSGalNAcT-1 underlying the pathogenesis of DD-II.
