Mutations in DSPP cause a range of autosomal dominant dental diseases, including dentin dysplasia type 2 (DD-II),(20) dentinogenesis imperfecta type 2 (DGI-II),(21) and dentinogenesis imperfecta type 3 (DGI-III).(22) To date, no other gene besides DSPP has been associated with isolated inherited dentin defects.(2,14) Dspp null mice display severe dentin malformations,(23) while transgenic expression of only the N-terminal domain (Dsp) in the null background partially rescues the dentin phenotype.(24) The volume of dentin but not the dentin mineral density is restored. Here, DSP is linked to dentin dysplasia type II.