Protein Tyrosine Phosphatase Non-receptor 22 Gene C1858T Polymorphism in Patients with Coexistent Type 2 Diabetes and Hashimoto's Thyroiditis

Abstract

Background:A protein tyrosine phosphatase non-receptor type22 (PTPN22) C1858T genepolymorphism hasbeenreported to beasso-ciated withbothType 2 diabetes mellitus (T2DM) andHashimoto's thyroiditis (HT) separately. However, nostudy hasbeenconducted toexplore theC1858T polymorphism in T2DM andHT coexistent cases up to now. Aims:Thestudy aimed to determine whether a relationship exists or notbetween thePTPN22 C1858T polymorphism andthiscoexistent patient group.Study Design: Case-control study.Methods:Peripheral blood samples from 135T2DM patients, 102 patients withcoexistent T2DM+HT, 71HT patients and135healthycontrols were collected intoethylenediaminetetraacetic acid(EDTA)anticoagulant tubes andgenomic DNA wasextracted. ThePTPN22C1858T polymorphism wasanalyzed using polymerase chain reaction(PCR) restriction fragment length polymorphism (RFLP) methods.Results:Statistically significant differences were notobserved be-tween thepatient andcontrol groups. Thisstudy demonstrated a sta-tistically significant association between boththeCT genotype and theT allele inthefemale patient group withcoexistent T2DM+HT(CT genotype: p=0.04; T allele: p=0.045) witha statistically signifi-cantassociation between theCT genotype andthemean values of body mass index (BMI) andfreeT3levels (FT3) (BMI: p=0.044 and FT3: p=0.021) thatwasdetected inthepatient group withcoexis-tentT2DM+HT. Theminor genotype TT wasobserved innone of thegroups inthisstudy. TheCT genotype frequency was[number (frequency): 5 (3.8%), 7 (6.86%), 5 (7.04%), 3 (2.22%), while the Tallele frequency was5 (1.86%), 7 (3.44%), 5 (3.53%) and3 (1.12%)] in the T2DM, T2DM+HT, HT and control groups, respectively. Conclusion:Ourdatasuggest thatthePTPN22 1858T allele andthe CT genotype areassociated withincreased riskin female patients for coexistent T2DM+HT. TheCT genotype wasassociated withhigh mean BMI andfreeT3values inthepatient group withcoexistent T2DM+HT. These results demonstrate thatT allele carriers were more often in theT2DM+HT group thanin theT2DM group. There-fore, thecombination ofT2DM andHTwithfemale gender may havehigher T allele carriage incomparison totheT2DM onlyand male groups.