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Tooth Agenesis (tooth + agenesi)

Distribution by Scientific Domains

Medical Sciences	85%

Selected Abstracts

PAX9 polymorphisms and susceptibility to sporadic tooth agenesis: a case,control study in southeast China

EUROPEAN JOURNAL OF ORAL SCIENCES, Issue 2 2008
Yongchu Pan
Tooth agenesis is one of the most common developmental disorders in humans. The PAX9 gene, which plays an important role in odontogenesis, is associated with familial and sporadic tooth agenesis. A case,control study was performed in 102 subjects with tooth agenesis (cases) and 116 healthy controls. We genotyped four PAX9 gene polymorphisms using a polymerase chain reaction,restriction fragment length polymorphism (PCR-RFLP) assay. The allele and genotype frequencies of the four polymorphisms were not significantly different between the controls and the subjects with tooth agenesis. Similar results were observed in a subgroup analysis of test subjects only with mandibular incisor agenesis. Further analysis showed no significant difference in the haplotype distribution between the controls and the subjects with tooth agenesis or mandibular incisor agenesis. However, we found that the AGGC haplotype was associated with a decreased risk of tooth agenesis, compared with the most common haplotype, AGCC (odds ratio, 0.14; 95% confidence interval: 0.00,0.95). These results suggest that the four PAX9 polymorphisms alone have a non-significant main effect on the risk of tooth agenesis but that the AGGC haplotype may have a protective effect associated with a decreased risk of tooth agenesis. [source]

Low frequency of AXIN2 mutations and high frequency of MUTYH mutations in patients with multiple polyposis,,

HUMAN MUTATION, Issue 10 2006
Sophie Lejeune
Abstract Familial adenomatous polyposis has been linked to germline mutations in the APC tumor suppressor gene. However, a number of patients with familial adenomatous polyposis (with either classical or attenuated phenotype) have no APC mutation. Recently, germline mutations in the Wnt pathway component gene AXIN2 have been associated with tooth agenesis-colorectal cancer syndrome. Moreover, biallelic mutations in the base excision repair gene MUTYH have been associated with polyposis and early-onset colorectal cancer. The aim of this study was to further assess the contribution of AXIN2 and MUTYH to hereditary colorectal cancer susceptibility. AXIN2 and MUTYH genes were screened for germline mutations by PCR and direct sequencing in 39 unrelated patients with multiple adenomas or colorectal cancer without evidence of APC mutation nor mismatch repair defect. Two novel AXIN2 variants were detected in one patient with multiple adenomas, but no clearly pathogenic mutation. In contrast, nine different MUTYH mutations were detected in eight patients, including four novel mutations. Biallelic MUTYH mutations were only found in patients with multiple adenomatous polyposis (7 out of 22 (32%)). Interestingly, five MUTYH mutation carriers had a family history consistent with dominant inheritance. Moreover, one patient with biallelic MUTYH mutations presented with multiple adenomas and severe tooth agenesis. Therefore, germline mutations are rare in AXIN2 but frequent in MUTYH in patients with multiple adenomas. Our data suggest that genetic testing of MUTYH may be of interest in patients with pedigrees apparently compatible with autosomal recessive as well as dominant inheritance. © 2006 Wiley-Liss, Inc. [source]

Mutations in the PAX9 gene in sporadic oligodontia

ORTHODONTICS & CRANIOFACIAL RESEARCH, Issue 3 2010
E Pawlowska
To cite this article: Pawlowska E, Janik-Papis K, Poplawski T, Blasiak J, Szczepanska J: Mutations in the PAX9 gene in sporadic oligodontia Orthod Craniofac Res 2010;13:142,152 Structured Abstract Authors,,, Pawlowska E, Janik-Papis K, Poplawski T, Blasiak J, Szczepanska J Objectives,,, Oligodontia, a congenital lack of six or more teeth, is often associated with mutations in the PAX9 gene; therefore, we searched for mutations in this gene. Design,,, In the present work, we sequenced fragments of the PAX9 gene in individuals with sporadic oligodontia. Next, we genotyped some mutations we found in patients with oligodontia and individuals without tooth agenesis. Setting and Sample Population,,, DNA sequencing was performed in the material isolated from peripheral blood lymphocytes of six unrelated patients with sporadic, non-syndromic oligodontia. These patients were selected based upon explorative cluster analysis. Genotyping was performed in 38 patients with oligodontia and 100 control individuals. Material and Methods,,, Direct sequencing and restriction fragment length polymorphism PCR were employed. Results,,, We detected two homozygotic substitutions, IVS2-109G>C and IVS2-54A>G, in intron 2 in three patients. Another homozygotic substitution in intron 2, IVS2-41A>G, was revealed in two patients. Two patients had an IVS3+40G>A homozygotic change in intron 3 and 4 patients displayed a 717C>T transition in exon 4 (silent mutation). One patient had a heterozygotic 718G>C transversion, resulting in a missense Ala240Pro substitution. We detected also several other intronic substitutions. Further genotyping of the IVS2-54A>G, IVS2-109G>C, and IVS2-41A>G mutations suggested that they can display polymorphic changes. Conclusion,,, The IVS2-54A>G, IVS2-109G>C, and IVS2-41A>G mutations of the PAX9 gene may represent polymorphism associated with sporadic oligodontia. [source]

Investigating the etiology of multiple tooth agenesis in three sisters with severe oligodontia

ORTHODONTICS & CRANIOFACIAL RESEARCH, Issue 1 2008
S Swinnen
Structured Abstract Authors,,, Swinnen S, Bailleul-Forestier I, Arte S, Nieminen P, Devriendt K, Carels C Objectives,,, To describe the dentofacial phenotypes of three sisters with severe non-syndromic oligodontia, to report on the mutation analysis in three genes, previously shown to cause various phenotypes of non-syndromic oligodontia and in two other suspected genes. Based on the phenotypes in the pedigree of this family, the different possible patterns of transmission are discussed. Methods,,, Anamnestic data and a panoramic radiograph were taken to study the phenotype of the three sisters and their first-degree relatives. Blood samples were also taken to obtain their karyotypes and DNA samples. Mutational screening was performed for the MSX1, PAX9, AXIN2, DLX1 and DLX2 genes. Results,,, The probands' pedigree showed evidence for a recessive or multifactorial inheritance pattern. Normal chromosomal karyotypes were found and , despite the severe oligodontia present in all three sisters , no mutation appeared to be present in the five genes studied so far in these patients. Conclusions,,, In the three sisters reported, their common oligodontia phenotype is not caused by mutations in the coding regions of MSX1, PAX9, AXIN2, DLX1 or DLX2 genes, but genetic factors most probably play a role as all three sisters were affected. Environmental and epigenetic factors as well as genes regulating odontogenesis need further in vivo and in vitro investigation to explain the phenotypic heterogeneity and to increase our understanding of the odontogenic processes. [source]