ABSTRACT Objective: We aimed to investigate the role of DIO2 polymorphisms rs225014 and rs12885300 in Graves’ disease patients, mainly for controlling body weight following treatment. Subjects and methods: We genotyped 280 GD patients by the time of diagnosis and 297 healthy control individuals using a TaqMan SNP Genotyping technique. We followed up 141 patients for 18.94 ± 6.59 months after treatment. Results: There was no relationship between the investigated polymorphisms with susceptibility to GD and gain or loss of weight after GD treatment. However, the polymorphic inheritance (CC+CT genotype) of DIO2 rs225014 was associated with a lower body weight variation after GD treatment (4.26 ± 6.25 kg) when compared to wild type TT genotype (6.34 ± 7.26 kg; p = 0.0456 adjusted for the follow-up time). This data was confirmed by a multivariate analysis (p = 0.0138) along with a longer follow-up period (p = 0.0228), older age (p = 0.0306), treatment with radioiodine (p-value = 0.0080) and polymorphic inheritance of DIO2 rs12885300 (p = 0.0306). Conclusion: We suggest that DIO2 rs225014 genotyping may have an auxiliary role in predicting the post-treatment weight behavior of GD patients.

ABSTRACT Objective: Selenium (Se) supplementation has been used to help prevent the progression of Graves’ ophthalmopathy (GO) and autoimmune thyroid diseases (AITD) patients. We investigated Se serum and selenoprotein P (SePP) levels in Graves’ disease (GD) with and without GO, Hashimoto's thyroiditis (HT) patients and in 27 control individuals (C). Subjects and methods: We studied 54 female and 19 male patients: 19 with GD without GO, 21 GD with GO, 14 with HT and 19 with HT+LT4. Se values were measured using graphite furnace atomic absorption spectrophotometry. Serum SePP levels were measured by ELISA. Results: Median Se levels were similar among all groups; GD patients: 54.2 (46.5-61.1 μg/L), GO: 53.6 (43.5-60.0 μg/L), HT: 51.9 (44.6-58.5 μg/L), HT+LT4 54.4 (44-63.4) and C group patients: 56.0 (52.4-61.5 μg/L); P = 0.48. However, serum SePP was lower in GO patients: 0.30 (0.15-1.05 μg/mL) and in HT patients: 0.35 (0.2-1.17 μg/mL) compared to C group patients: 1.00 (0.564.21 μg/mL) as well as to GD patients: 1.19 (0.62-2.5 μg/mL) and HT+LT4 patients: 0.7 (0,25-1.95); P = 0.002. Linear regression analysis showed a significant relationship between SePP and TPOAb values (r = 0.445, R2 = 0.293; P < 0.0001). Multiple regression analysis found no independent variables related to Se or SePP. Conclusion: A serum Se concentration was lower than in some other countries, but not significantly among AITD patients. The low serum SePP levels in GO and HT patients seems to express inflammatory reactions with a subsequent increase in Se-dependent protein consumption remains unclear.