OBJECTIVETo analyze the clinical phenotype of a Chinese pedigree affected with hereditary dentinogenesis imperfecta and mutation of dentin sialophosphoprotein (DSPP) gene.

METHODSAffected members underwent intraoral photography, dental film and panoramic radiography. Genomic DNA was extracted from peripheral venous blood samples. Coding regions of the DSPP gene were subjected to PCR amplification and Sanger sequencing. Functional effect of the mutation was predicted with SIFT and PolyPhen-2. The tertiary structure of wild type and mutant proteins were predicted by Swiss-Port.

RESULTSA heterozygous c.50C to T (p.P17L) mutation was identified in exon 2 of the DSPP gene in the proband and her father. The same mutation was not found among 200 unrelated healthy controls. The Pro-17 residues and its surrounding positions in DSPP are highly conserved across various species. The mutation was predicted to be damaging to the structure of DSPP protein.

CONCLUSIONThe c.50C to T (p.P17L) mutation of the DSPP gene probably underlies the disease in this pedigree. Above finding has expanded the spectrum of DSPP gene mutations and provided a basis for genetic counseling and prenatal diagnosis for this family.