Identification of the DSPP mutation in a new kindred and phenotype-genotype correlation.

[dentin dysplasia]

Hereditary dentin defects can be grouped into three types of dentinogenesis imperfecta (DGI ) and two types of dentin dysplasia . Tooth enamel is considered normal in patients with hereditary dentin defects , but is easily worn down and fractured due to DSPP mutation -induced altered dentin properties . The purposes of this study were to identify genetic cause of a family with type II DGI and enamel defects .We identified a family with type II DGI and a unique form of hypoplastic enamel defect affecting occlusal third of the crown . Family members were recruited for the genetic analysis and DNA was obtained from peripheral whole blood .Mutational analysis revealed a T to A transversion in exon 3 of the DSPP (c .53 T >A , p .V 18 D ). 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 . Clinical features suggest that enamel formation was affected in the affected individuals during early amelogenesis , in addition to the dentin defect .We observed that a DSPP gene mutation not only influences dentinogenesis but also affects early stage amelogenesis .