OBJECTIVE: To explore the clinical and genetic characteristics of a Chinese pedigree affected with hereditary dentinogenesis imperfecta (DGI) type II. METHODS: Clinical data of the pedigree members were collected. Genomic DNA was extracted from peripheral blood samples and subjected to whole exome sequencing. RESULTS: Clinical characteristics of the affected family members have included amber teeth along with significant attrition, constricted roots and dentine hypertrophy leading to pulpal obliteration, which were suggestive of DGI type II. All of the affected members were found to have harbored a novel heterozygous c.2837delA (p.Asp946Valfs*368) variant of the DSPP gene which was predicted to be likely pathogenic. CONCLUSION The c.2837delA variant of the DSPP gene probably underlay the disease in this pedigree. Above finding has expanded the variant spectrum of DSPP gene and provided a basis for molecular diagnosis and genetic counseling for this pedigree.
Dentinogenesis Imperfecta/genetics* ; Extracellular Matrix Proteins/genetics* ; Humans ; Mutation ; Pedigree ; Phosphoproteins/genetics* ; Sialoglycoproteins/genetics*

The classification as well as the clinical manifestations of hereditary malformations of dentin are of great concern and have been deeply elucidated. The understanding of its genetic basis also increases progressively. Dentin sialophosphoprotein (DSPP) is the pathogenic gene of dentinogenesis imperfecta type Ⅱ, dentinogenesis imperfecta type Ⅲ and dentin dysplasia type Ⅱ. In this article, the classification of DSPP mutations as well as the resultant dysfunction of the mutant DSPP are summarized respectively and the corresponding clinical manifestations are analyzed. This work will provide a reference for the diagnosis and treatment of hereditary malformations of dentin.
Humans ; Dentinogenesis Imperfecta/pathology* ; Mutation ; Extracellular Matrix Proteins/genetics* ; Phosphoproteins/genetics* ; Sialoglycoproteins/genetics* ; Dentin/pathology*

OBJECTIVE: To analyze the clinical characteristics and the genetic cause of a Chinese patient with hereditary opalescent dentin, and to make an observation of the histologic and elemental features of the affected teeth. METHODS: We enrolled a patient affected with hereditary opalescent dentin. The medical history was collected and clinical examinations were performed for the phenotypic analyses. The blood sample was collected for DNA extraction and PCRs of the coding sequence of DSPP were done for sanger sequencing. The teeth samples were collected for histological evaluation and elemental analysis. RESULTS: The patient showed typical clinical manifestations of opalescent dentin and had enamel dysplasia and skeletal class III malocclusion. Several polymorphisms (c.727G>A, c.897A>G, c.2053_2054ins18bp, c.2548G>A, c.2645_2646ins9bp, c.2706T>C, c.2878A>G, c.3004A>G, c.3069_3086del18bp, c.3249A>C, c.3264T>C, c.3266_3400del135bp, c.3418A>G, c.3454G>A, c.3461_3462ins18bp, c.3606C>T) but no pathogenic mutations were identified in DSPP. The histological analyses of the patient's teeth showed characteristic abnormalities that were significantly different from normal teeth. The dentin tubules of the affected teeth were decreased in number and sparsed in arrangement, while in the control teeth, they were more regular. The enamel-dentin junction of the affected teeth was abnormal in its less scallopped outline compared with the control teeth under the scanning electronic microscopy. The Mg proportion of the patient's teeth (0.615 0%±0.261 6%) was lower than that of the control teeth (1.283 3%±0.322 1%), the P value was 0.040. The Ca proportion was the higher compared with the control teeth (34.865 0%±0.388 9% vs. 29.221 7%±2.248 4%), the P value was 0.015. The Ca/P ration of the patient's teeth was 1.981 2±0.019 3, which was higher than that of control teeth (1.775 9±0.111 6), the P value was 0.049. The differences of Mg, Ca proportion and Ca/P ration between the affected teeth and the control teeth were significant. The C and O proportion of the patient's teeth were lower and the P proportion was higher compared with the control teeth, however, the differences were not significant. CONCLUSION Our study of clinical manifestation analysis, genetic variants sequencing and histological observation has enlarged the phenotypic spectrum of hereditary opalescent dentin, and the genetic and histological results would contribute to further studies.
Dental Enamel ; Dentin ; Dentinogenesis Imperfecta/genetics* ; Genetic Testing ; Humans ; Polymorphism, Genetic ; Tooth

OBJECTIVETo identify the causative mutation in a Chinese family affected with dentinogenesis imperfecta shields type II (DGI-II).

METHODSWith informed consent obtained from all participants, peripheral blood or chorionic villi samples were collected from the family members. Genomic DNA was extracted using a standard SDS-proteinase K-phenol/chloroform method. The whole coding region and exon/intron boundaries of the DSPP gene were amplified with polymerase chain reaction (PCR) and subjected to Sanger sequencing. To confirm the pathogenicity of the identified mutation, an Alu I recognition sequence was introduced into the mutant allele using mismatch primers by semi-nested PCR. Restriction fragment length polymorphism (RFLP) analysis was then carried out for all family members and 60 unrelated healthy controls. Meanwhile, mini-DSPP constructs were conducted to confirm the effect of the mutation in vitro.

RESULTSA splicing site mutation, c.52-1G>A, which was located upstream of exon 3, was found in all three patients and the fetus of the proband. Restriction analysis confirmed that all unaffected individuals and the 60 healthy controls did not carry the same mutation. The expression of minigene showed that the exon 3 of the DSPP gene was skipped during the transcription.

CONCLUSIONA novel pathogenic splicing-mutation c.52-1G>A has been detected in a Chinese family affected with DGI-II, which enabled prenatal diagnosis for the fetus of the proband.

Adult ; Asian Continental Ancestry Group ; genetics ; Base Sequence ; Child, Preschool ; Dentinogenesis Imperfecta ; genetics ; Exons ; Extracellular Matrix Proteins ; genetics ; Female ; Humans ; Male ; Molecular Sequence Data ; Pedigree ; Phosphoproteins ; genetics ; Point Mutation ; RNA Splicing ; Sialoglycoproteins ; genetics

OBJECTIVETo investigate the linkage between dentinogenesis imperfecta type II and chromosome 4q21 in a Tianjin-Tanggu family of the Hui nationality.

METHODSBlood samples were collected from 13 family members. DNAs were analyzed with 8 STRP markers (D4S2915, D4S2932, GATA62A11, D4S2409, DSP STRP, SPP1 STRP, D4S1563, D4S1544) using fluorescence-based PCR. The linkage between eight markers on chromosome 4q21 and dentinogenesis imperfecta type II locus was tested respectively by lod score analysis.

RESULTSGenotype and haplotype were acquired. Genetic linkage analysis demonstrated the maximum lod score of eight STRPs were all larger than zero, in which five of them were larger than 1.

CONCLUSIONThe locus of dentinogenesis imperfecta type II in Chinese family is located on human chromosome 4q21, which indicated that the locus of Chinese Hui nationality should be the same as that of other reported European or American family.

Chromosome Mapping ; Chromosomes, Human, Pair 4 ; genetics ; DNA ; genetics ; Dentinogenesis Imperfecta ; genetics ; pathology ; Family Health ; Female ; Genetic Linkage ; Genetic Predisposition to Disease ; genetics ; Humans ; Male ; Microsatellite Repeats ; Pedigree ; Polymerase Chain Reaction

OBJECTIVETo study the genetic etiology of an autosomal dominant dentinogenesis imperfecta in a Chinese family.

METHODSThe molecular change of the disease in the family was analyzed through the clinical examination, linkage analysis, mutational screening of the DSPP gene and restriction fragment length polymorphism analysis.

RESULTSThe disease related gene was completely linked with microsatellite marker D4S1534. We found a novel mutation in the first exon of the DSPP gene (c.49C>T, p.Pro17Ser). All patients in the family had the mutation, while this mutation was not observed in the normal individuals of this family and 100 unrelated controls.

CONCLUSIONThe p.Pro17Ser identified in the family was a new pathogenic mutation. Our finding provided further understanding of the molecular mechanism of dentinogenesis imperfecta.

Amino Acid Sequence ; Asian Continental Ancestry Group ; genetics ; Base Sequence ; Dentinogenesis Imperfecta ; genetics ; Exons ; Extracellular Matrix Proteins ; genetics ; Female ; Humans ; Male ; Microsatellite Repeats ; Molecular Sequence Data ; Mutation ; Pedigree ; Phosphoproteins ; Sialoglycoproteins ; Young Adult