The aims of this study were to assess genotype-phenotype findings in three families with DI-II with special reference to mutations in the DSPP gene and clinical, histological, and imaging manifestations.
Hereditary dentin defects can be categorised into two classes according to their clinical manifestations: dentinogenesis imperfecta (DGI), which includes three types (DGI-I, DGI-II and DGI-III), and dentin dysplasia (DD), which includes two types (DD-I and DD-II).
Human mutations of this DSPP gene are responsible for three isolated dentinal diseases classified by Shield in 1973: type II and III dentinogenesis imperfecta and type II dentin dysplasia.
Rough endoplasmic reticulum trafficking errors by different classes of mutant dentin sialophosphoprotein (DSPP) cause dominant negative effects in both dentinogenesis imperfecta and dentin dysplasia by entrapping normal DSPP.
Hereditary dentine disorders dentinogenesis imperfecta type II/III and dentine dysplasia are currently proposed to be one disease with distinct clinical manifestations reflecting various mutations in the same DSPP gene.
Dentin sialophosphoprotein (DSPP) mutations cause dentin dysplasia type II (DD-II) and dentinogenesis imperfecta types II and III (DGI-II and DGI-III, respectively).
We recruited three Korean families with dentinogenesis imperfecta (DGI) type II and sequenced the exons and exon-intron boundaries of the DSPP gene based on the candidate gene approach.
Haplotype analysis showed that the same mutation arose separately in two different families having DGI with similar enamel defects, indicating that this phenotype is associated with this specific DSPP mutation.
Targeted disruption of the dentin sialophosphoprotein (DSPP) gene in the mice (Dspp(-/-)) results in dentin mineralization defects with enlarged predentin phenotype similar to human dentinogenesis imperfecta type III.
Within nine dentin dysplasia (DD) (type II) and dentinogenesis imperfecta (type II and III) patient/families, seven have 1 of 4 net -1 deletions within the approximately 2-kb coding repeat domain of the DSPP gene while the remaining two patients have splice-site mutations.