A novel splice site mutation in the dentin sialophosphoprotein gene in a Chinese family with dentinogenesis imperfecta type II.
Twenty-four individuals were investigated that spanned six generations in a Chinese family affected with an apparently autosomal dominant form of dentinogenesis imperfecta type II (DGI-II, OMIM #125490). All affected individuals presented with typical, clinical and radiographic features of DGI-II, but without bilateral progressive high-frequency sensorineural hearing loss. To investigate the mutated molecule, a positional candidate approach was used to determine the mutated gene in this family. Genomic DNA was obtained from 24 affected individuals, 18 unaffected relatives of the family and 50 controls. Haplotype analysis was performed using leukocyte DNA for 6 short tandem repeat (STR) markers present in chromosome 4 (D4S1534, GATA62A11, DSPP, DMP1, SPP1 and D4S1563). In the critical region between D4S1534 and DMP1, the dentin sialophosphoprotein (DSPP) gene (OMIM *125485) was considered as the strongest candidate gene. The first four exons and exon/intron boundaries of the gene were analyzed using DNA from 24 affected individuals and 18 unaffected relatives of the same family. DNA sequencing revealed a heterozygous deletion mutation in intron 2 (at positions -3 to -25), which resulted in a frameshift mutation, that changed the acceptor site sequence from CAG to AAG (IVS2-3C-->A) and may also have disrupted the branch point consensus sequence in intron 2. The mutation was found in the 24 affected individuals, but not in the 18 unaffected relatives and 50 controls. The deletion was identified by allele-specific sequencing and denaturing high-performance liquid chromatography (DHPLC) analysis. We conclude that the heterozygous deletion mutation contributed to the pathogenesis of DGI-II.
Wang
HaoYang
H
Institute of Laboratory Medicine, Jinling Hospital, School of Medicine, Nanjing University, Nanjing 210002, PR China.
Hou
YanNing
Y
Cui
YingXia
Y
Huang
YuFeng
Y
Shi
YiChao
Y
Xia
XinYi
X
Lu
HongYong
H
Wang
YunHua
Y
Li
XiaoJun
X
D000293:Adolescent; D000368:Aged; D044466:Asian People / Q000235:genetics*; D001483:Base Sequence; D002681:China; D002851:Chromatography, High Pressure Liquid; D004252:DNA Mutational Analysis; D003811:Dentinogenesis Imperfecta / Q000235:genetics*; D005091:Exons / Q000235:genetics; D016326:Extracellular Matrix Proteins / Q000235:genetics*; D005190:Family; D005260:Female; D008040:Genetic Linkage; D006238:Haploidy; D006801:Humans; D007223:Infant; D008297:Male; D008875:Middle Aged; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics*; D009691:Nucleic Acid Denaturation; D010375:Pedigree; D010750:Phosphoproteins; D022821:RNA Splice Sites / Q000235:genetics*; D012795:Sialoglycoproteins; D000099311:Dentin Sialophosphoprotein
D016326:Extracellular Matrix Proteins; D010750:Phosphoproteins; D022821:RNA Splice Sites; D012795:Sialoglycoproteins; D000099311:Dentin Sialophosphoprotein