Genetic Polymorphism in MMP9 May Be Associated With Anterior Open Bite in Children.

Erika Calvano Küchler,Júlia Guimarães Barcellos De Abreu,Driely Barreiros,Paulo Nelson Filho,Leonardo Santos Antunes,Fábio Lourenço Romano,Ellen Cardoso Teixeira,Lea Assed Bezerra Da Silva,Raquel Assed Bezerra Da Silva,Raphaela Oliveira Da Silva,Lívia Azeredo Alves Antunes,José Mauro Granjeiro

doi:10.1590/0103-6440201600992

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.

Highlights

Anterior Open Bite (AOB) is a dentoalveolar or skeletal malocclusion in the vertical plane [1], with the lack of contact of opposing teeth when posterior teeth are in occlusion [2]
It is possible that AOB is influenced by genetic factors [3,8], in which genes that play a role in facial bone growth and development, teeth and soft tissue, may be associated with AOB
Genotyping of the selected polymorphisms in MMP2, MMP3, MMP9, TIMP1 and TIMP2 was carried out by real-time PCR using the Stratagene Mx3005P (Agilent Techologies, SAN Diego, CA, USA) with TaqMan method that expresses each sample as a homozygotic or heterozygotic according to the detected fluorescence

Summary

Introduction

Anterior Open Bite (AOB) is a dentoalveolar or skeletal malocclusion in the vertical plane [1], with the lack of contact of opposing teeth when posterior teeth are in occlusion [2]. Sucking habits and facial characteristics such as bone, teeth and soft tissue alterations are involved in AOB etiology [3]. It is possible that AOB is influenced by genetic factors [3,8], in which genes that play a role in facial bone growth and development, teeth and soft tissue, may be associated with AOB. MMPs and TIMPs, are involved in tissue modelling and remodeling [11,12,13] and play an important role during organogenesis, growth and normal tissue turnover [14]. There is no published paper on the association between AOB and genetic factors, it is plausible to hypothesize that genetic factors act in combination with sucking habits establishing the AOB in children. The aim of this study was to evaluate the association between polymorphism in MMP2, MMP3, MMP9, TIMP1 and TIMP2 genes with AOB

Material and Methods

Results

Discussion