The Relationships Between Thyroid Function Tests and Insulin Receptor Substrate Gene Polymorphisms in Patients with Metabolic Syndrome

Presentation Number: MON-0383
Date of Presentation: June 23rd, 2014

Fulden Zeliha Sarac*1, Sefa Sarac2, Sumru Savas1 and Fehmi Akcicek3
1School of Medicine, Ege University, Izmir, Turkey, 2Atatürk Training and Research Hospital, Izmir, Turkey, 3Ege University Medical Faculty, Izmir, Turkey

Abstract

Introduction: Metabolic syndrome (MetS) can be associated with endocrinal and nonendocrinal disorders and has widespread consequences. The aims of the study were 1.  To compare the thyroid function tests, and 2. to evaluate the relationships between  insulin receptor substrat-1 (IRS-1) and insulin receptor substrat-2 (IRS-2) gene polymorphisms and thyroid function tests such as TSH, free (F) T3, and free (F) T4  in patients with MetS and without MetS.

Subjects and Methods: The study population included 100 patients with MetS and 30 patients without MetS as control group. All entire coding exons of IRS-1 and IRS- 2 gene were amplified by polymerase chain reaction (PCR). Insulin resistance (IR) was estimated using the homeostasis model assessment (HOMA-IR).

Results: In patients with MetS, 34 (34%) patients had G972R gene polymorphism and 66 (66%) had no nucleotide substitution at IRS-1 gene (p<0.0001). And also, in IRS-2 gene, 44 (44%) had no nucleotide substitution, 18 (18%) had G1057D heterozygous, 11 (11.0%) had G1057D homozygous, 2 (2%) had P1031P heterozygous/P1033PG1057 heterozygous, 17 (17.0%) had P1033P heterozygous, 3 (3.0%) had P1033P homozygous and 5 (5%) had P1033P heterozygous/G 1067D heterozygous polymorphisms in MetS. Mean levels of TSH, FT3, and fT4 were found to be 2.7±0.9 μIU/ml, 3.2±0.5 pg/ml and 1.2±0.2 ng/dl, respectively, in patients with MetS. In patients without MetS, mean levels of TSH, FT3, and FT4 were found to be 2.2±0.7 μIU/ml, 3.1±0.2 pg/ml and 1.2±0.2 ng/dl, respectively. Mean levels of TSH were statistically significantly higher in patients with MetS than that of patients without MetS (p=0.02) but not FT3, and fT4 levels (p=0.76), (p=0.26), respectively. In patients with MetS, mean levels of TSH were positively correlated with HOMA-IR levels (r=0.850, p=0.001). Mean levels of TSH were positively correlated with G972R gene polymorphism at IRS-1 gene (r= 0.400, p=0.03) in patients with MetS. However, mean levels of FT3 were positively correlated with G1057D homozygous gene polymorphism at IRS-2 gene in patients with MetS.

Conclusion: Mean levels of TSH were positively correlated with G972R gene polymorphism at IRS-1 gene in patients with MetS. And also, mean levels of FT3 were positively correlated with G1057D homozygous gene polymorphism at IRS-2 gene in patients with MetS.

 

Nothing to Disclose: FZS, SS, SS, FA