Frameshift mutations in dentin phosphoprotein and dependence of dentin disease phenotype on mutation location.
We describe results from a mutational analysis of the region of the dentin sialophosphoprotein (DSPP) gene encoding dentin phosphoprotein (DPP) in 12 families with dominantly inherited dentin diseases. In eight families (five mutations in the N-terminal third of DPP), the clinical and radiologic features were uniform and compatible with dentin dysplasia type II (DD-II) with major clinical signs in the deciduous dentition. In the other families (four mutations in the more C-terminal part), the permanent teeth also were affected, and the diseases could be classified as variants of dentinogenesis imperfecta. Attrition was not prominent, but periapical infections were common. Discoloring with varying intensity was evident, and pulps and root canals were obliterated in the permanent dentition. All mutations caused a frameshift that replaced the Ser-Ser-Asx repeat by a code for a hydrophobic downstream sequence of approximately original length. We conclude that frameshift mutations in DSPP explain a significant part of dentin diseases. Furthermore, we propose that the location of the mutation is reflected in the phenotypic features as a gradient from DD-II to more severe disease that does not conform to the classic definitions of DI-II.
Institute of Dentistry, Biomedicum, University of Helsinki, Helsinki, Finland. pekka.nieminen@helsinki.fi
Pekka
P
Nieminen
Lisa
L
Papagiannoulis-Lascarides
Janna
J
Waltimo-Siren
Päivi
P
Ollila
Sara
S
Karjalainen
Sirpa
S
Arte
Jaap
J
Veerkamp
Victoria
V
Tallon Walton
Eduard
E
Chimenos Küstner
Tarja
T
Siltanen
Heidi
H
Holappa
Pirjo-Liisa
PL
Lukinmaa
Satu
S
Alaluusua
D000293:Adolescent; D000328:Adult; D000567:Amelogenesis Imperfecta / Q000175:diagnosis / Q000000981:diagnostic imaging / Q000235:genetics / Q000473:pathology; D000595:Amino Acid Sequence; D002648:Child; D002675:Child, Preschool; D003784:Dental Pulp Calcification; D003805:Dentin Dysplasia / Q000175:diagnosis / Q000000981:diagnostic imaging / Q000235:genetics* / Q000473:pathology*; D003811:Dentinogenesis Imperfecta / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000235:genetics* / Q000473:pathology*; D005091:Exons / Q000235:genetics; D016326:Extracellular Matrix Proteins / Q000235:genetics*; D005190:Family; D016368:Frameshift Mutation / Q000235:genetics*; D006579:Heterozygote; D006801:Humans; D057927:Hydrophobic and Hydrophilic Interactions; D008969:Molecular Sequence Data; D010375:Pedigree; D010641:Phenotype; D010750:Phosphoproteins / Q000235:genetics*; D011859:Radiography; D012795:Sialoglycoproteins / Q000235:genetics*; D014070:Tooth / Q000000981:diagnostic imaging / Q000473:pathology; D014071:Tooth Abnormalities / Q000000981:diagnostic imaging / Q000473:pathology; D014094:Tooth, Deciduous / Q000002:abnormalities / Q000000981:diagnostic imaging / Q000473:pathology; D055815:Young Adult; D000099311:Dentin Sialophosphoprotein
D016326:Extracellular Matrix Proteins; D010750:Phosphoproteins; D012795:Sialoglycoproteins; D000099311:Dentin Sialophosphoprotein