Does the polymorphism in the length of the polyalanine tract of FOXE1 gene influence the risk of thyroid dysgenesis occurrence?

Fundação de Amparo à Pesquisa do Estado do Pará (FAPESPA, Grant no. 236/2009); ´ Capacitação e Aperfeiçoamento de Pessoal de Ensino Superior (CAPES), Instituto Nacional de Genética Médica Populacional (Edital de Genética Clínica/CNPq, Grant no. 402050/2010-0); and Conselho Nacional de Desenvolvimento Cientíıfico e Tecnológico (CNPq, Grant no. 573993/2008-4).Universidade Federal do Pará. Instituto de Ciências Fisiológicas. Laboratório de Erros Inatos do Metabolismo. Belém, PA, Brazil.Universidade Federal do Pará. Instituto de Ciências Fisiológicas. Laboratório de Erros Inatos do Metabolismo. Belém, PA, Brazil / Universidade do Estado do Pará. Departamento de Morfologia e Ciências Fisiológicas. Belém, PA, Brazil.Ministério da Saúde. Secretaria de Vigilância em Saúde. Instituto Evandro Chagas. Laboratório de Cultura de Tecidos e Citogenética. Ananindeua, PA, Brasil / Universidade Federal do Pará. Instituto de Ciências Exatas e Naturais. Belém, PA, Brazil.Universidade Federal do Pará. Instituto de Ciências Fisiológicas. Laboratório de Erros Inatos do Metabolismo. Belém, PA, Brazil.Background. Recent data have suggested that polymorphisms in the length of the polyalanine tract (polyA) of FOXE1 gene may act as a susceptibility factor for thyroid dysgenesis. The main purpose of this study was to investigate the influence of polyA of FOXE1 gene on the risk of thyroid dysgenesis. Method. A case-control study was conducted in a sample of 90 Brazilian patients with thyroid dysgenesis and 131 controls without family history of thyroid disease. Genomic DNA was isolated from peripheral blood samples and the genotype of each individual was determined by automated sequencing. Results. More than 90% of genotypes found in the group of patients with thyroid dysgenesis and in controls subjects were represented by sizes 14 and 16 polymorphisms in the following combinations: 14/14, 14/16, and 16/16. Genotypes 14/16 and 16/16 were more frequent in the control group, while genotype 14/14 was more frequent in the group of patients with thyroid dysgenesis. There was no difference between agenesis group and control group. Genotype 14/14 when compared to genotypes 14/16 and 16/16A showed an association with thyroid dysgenesis. Conclusion. PolyA of FOXE1 gene alters the risk of thyroid dysgenesis, which may explain in part the etiology of this disease