A dentin sialophosphoprotein mutation that partially disrupts a splice acceptor site causes type II dentin dysplasia.
The dentin sialophosphoprotein (DSPP) gene on chromosome 4q21.3 encodes the major noncollagenous protein in tooth dentin. DSPP mutations are the principal cause of dentin dysplasia type II, dentinogenesis imperfecta type II, and dentinogenesis imperfecta type III. We have identified a DSPP splice junction mutation (IVS2-6T>G) in a family with dentin dysplasia type II. The primary dentition is discolored brown with severe attrition. The mildly discolored permanent dentition has thistle-shaped pulp chambers, pulp stones, and eventual pulp obliteration. The mutation is in the sixth nucleotide from the end of intron 2, perfectly segregates with the disease phenotype, and is absent in 200 normal control chromosomes. An in vitro splicing assay shows that pre-mRNA splicing of the mutant allele generates wild-type mRNA and mRNA lacking exon 3 in approximately equal amounts. Skipping exon 3 might interfere with signal peptide cleavage, causing endoplasmic reticulum stress, and also reduce DSPP secretion, leading to haploinsufficiency.
Lee
Sook-Kyung
SK
Department of Cell and Developmental Biology, School of Dentistry and Dental Research Institute, Seoul National University, Seoul, Republic of Korea.
Hu
Jan C-C
JC
Lee
Kyung-Eun
KE
Simmer
James P
JP
Kim
Jung-Wook
JW
D000293:Adolescent; D000328:Adult; D002675:Child, Preschool; D002894:Chromosomes, Human, Pair 4 / Q000235:genetics; D003782:Dental Pulp / Q000002:abnormalities; D003784:Dental Pulp Calcification / Q000235:genetics; D003805:Dentin Dysplasia / Q000145:classification / Q000235:genetics*; D004721:Endoplasmic Reticulum / Q000378:metabolism; D005091:Exons / Q000235:genetics; D016326:Extracellular Matrix Proteins / Q000235:genetics*; D005260:Female; D006147:Guanine; D006801:Humans; D007438:Introns / Q000235:genetics; D008297:Male; D009154:Mutation / Q000235:genetics*; D010375:Pedigree; D010750:Phosphoproteins / Q000235:genetics*; D021382:Protein Sorting Signals / Q000235:genetics; D022821:RNA Splice Sites / Q000235:genetics*; D012795:Sialoglycoproteins / Q000235:genetics*; D013941:Thymine; D019217:Tooth Attrition / Q000235:genetics; D014075:Tooth Discoloration / Q000235:genetics; D014094:Tooth, Deciduous / Q000002:abnormalities; D000099311:Dentin Sialophosphoprotein
D016326:Extracellular Matrix Proteins; D006147:Guanine; D010750:Phosphoproteins; D021382:Protein Sorting Signals; D022821:RNA Splice Sites; D012795:Sialoglycoproteins; D013941:Thymine; D000099311:Dentin Sialophosphoprotein