the association study between deiodinase2 gene polymorphism with thyroid nodule

introduction: a thyroid nodule is a palpable swelling in a thyroid gland with an otherwise normal appearance. palpable thyroid nodules occur in 4 to 7 percent of the population. nodular thyroid diseases are more frequent in women than in men. most actions of thyroid hormone are mediated by the active form of thyroid hormone. d2 is essential for formation of active hormone of t3 through deiodination of triiodothyroxine. the single-nucleotide polymorphism d2 thr92ala is associated with decreased enzyme activity. the purpose of this study was to investigate an association of rs225014 deiodinase2 gene polymorphism with thyroid nodule. methods: a case-control study comprising 110 patients with thyroid nodule and 110 healthy controls was performed. thyroid nodule was established by ultrasonography. we analyzed d2 thr92ala polymorphism by tetra-arms pcr method. the distribution of alleles and genotypes of this polymorphism in two groups were determined and the data were analyzed by chi square and logistic regression analysis. results: in the 110 of case group, the frequency of tt, tc and cc genotypes of rs225014 polymorphism were 25(80.6%), 81(44%) and 4(80%), respectively that indicated  a significant difference compared with 110 of control group: tt 6(19.4%), tc 103(56%), cc 1(20%) (p 0.0001) conclusion: rs225014 polymorphism in d2 gene is associated with thyroid nodule. however, further multicenteric and functional studies with more participants and evaluation for other polymorphisms in d2 gene are necessary to determine why this association is exist and determine its mechanism.