No abstract

Anterior open bite (AOB) has a multifactorial etiology caused by the interaction of sucking habits and genetic factors. The aim of this study was to evaluate the association between AOB and polymorphisms in genes that encode Matrix metalloproteinases (MMPs) and their tissue inhibitors (TIMPs). Four hundred and seventy-two children that presented at least one sucking habit were evaluated. Children were examined clinically for the presence of AOB. Genomic DNA was extracted from saliva. Genotyping of the selected polymorphisms in MMP2, MMP3, MMP9, TIMP1 and TIMP2 was carried out by real-time PCR using the TaqMan method. Allele and genotype frequencies were compared between the groups with and without AOB using the PLINK® software in a free and in a recessive model using a chi-square test. Logistic regression analysis was implemented (p≤0.05). Two hundred nineteen children had AOB while 253 did not. The polymorphism rs17576 in MMP9 was significantly associated with AOB (p=0.009). In a recessive model GG genotype was a protective factor for AOB (p=0.014; OR 4.6, 95%CI 1.3-16.2). In the logistic regression analysis, none of the genes was associated with AOB. In conclusion, the polymorphism rs17576 (glutamine for arginine substitution) in MMP9 was a protective factor for AOB.

Background: The aim of the present study was to assess if genetic polymorphisms in tooth agenesis (TA)-related genes are associated with craniofacial morphological patterns. Methods: This cross-sectional, multi-center, genetic study evaluated 594 orthodontic Brazilians patients. The presence or absence of TA was determined by analysis of panoramic radiography. The patients were classified according to their skeletal malocclusion and facial growth pattern by means of digital cephalometric analysis. Genomic DNA was extracted from squamous epithelial cells of buccal mucosa and genetic polymorphisms in MSX1 (rs1042484), PAX9 (rs8004560), TGF-α (rs2902345), FGF3 (rs1893047), FGF10 (rs900379), and FGF13 (rs12838463, rs5931572, and rs5974804) were genotyped by polymerase chain reaction using TaqMan chemistry and end-point analysis. Results: Genotypes (p = 0.038) and allele (p = 0.037) distributions for the FGF3 rs1893047 were significantly different according to the skeletal malocclusion. Carrying at least one G allele increased in more than two times the chance of presenting skeletal class III malocclusion (OR = 2.21, CI 95% = 1.14-4.32; p = 0.017). There was no association between another skeletal craniofacial pattern and some polymorphism assessed in the present study. Conclusion: Our results suggest that the genetic polymorphism rs1893047 in FGF3 might contribute to variations in the craniofacial sagittal pattern.

No abstract

Bone development and growth is a non-going, life-long process, varying greatly among individuals and much of this variation could be modulated by genetic factors. The purpose of this study was to evaluate the association between the polymorphisms in the TNF-a gene and skeletal class II malocclusion. Single nucleotide polymorphisms in TNF-a (rs1799724; rs1800629) gene were studied in 79 skeletal class II malocclusion and 102 skeletal class I malocclusion subjects from Straight Wire Group of Studies on Orthodontics and Functional Orthopedics for Maxillary from Rio de Janeiro, Brazil. The Genotyping of these selected polymorphisms was carried out by TaqMan real-time PCR using genomic DNA extracted from buccal cells. All allele and genotype frequencies were compared between the groups using the PLINK® software in a free, in a dominant and in a recessive model using a chi-square test (p≤0.05). There was no significant association of TNF-a (rs1799724; rs1800629) genotype and allele distribution with skeletal class II malocclusion. Regardless of the dominant or recessive genetic model, the preferential genotype associations for rs1799724 and rs1800629 was insignificant. In conclusion, no evidence of association is apparent between genetic polymorphisms involving TNF-a and skeletal class II malocclusion or the position of the maxilla and mandible in the postero-anterior direction.