Endocrine Abstracts

Aim: Hashimoto Thyroiditis (HT); is the most common form of hpothyroidism in iodine-sufficient regions. Both genes and and environmental factors are involved in the immunopathological process of HT. Our aim in this study is to determine the prevalence of Thyrothropin Receptor (TSHR), Cytotoxic T Lypmhocyte Antigen-4 (CTLA-4) and Interleukin-1 Receptor Antagonist (IL-1RN) gene polymorphisms associated with HT in Turkish population and the relationship of genotype characteristics with phenotype.

Method: Patients with HT between the ages of 18-75 and healthy controls were included in this prospectively designed study. Clinical symptoms, iodine status according to the age of 6-15 and last city of residence asked in questionnaire and thyroid ultrasonography (USG) were performed in the participants. Peripheral blood was collected from participants for genetic analysis.

Results: The mean age of 244 patients (220 females,24 males) participating in the study was 40.84 years (min-max:18-75); The average age of 107 controls (91 females,16 males) is 38.37 years (min-max:19-65). In the 6-15 age range, the iodine adequacy of the cities where the patients live was found to be significantly higher than the control group (59.46%vs.41.00%; P=0.002). Except for dry skin (P=0.167) and weight gain (P=0.968), hypothyroidism symptoms and signs were significantly correlated with the disease in the Hashimoto group (P< 0.05). All controls were euthyroid. On the other hand 56.97% of the patients were euthyroid, 26% were subclinical hypothyroid, 11.07% were overt hypothyroid and 5.33% were hyperthyroid (P=<0.001). No difference was found between the patient and control groups in terms of thyroid volumes in thyroid USG (P=0.506). There was no significant difference in TSHR, CTLA-4, IL-1RN polymorphism distributions between HT patients and controls (P> 0.05). No association was also found between genotype and clinical parameters of patients with HT except the incidence of hypertension in TSHR GC polymorphism in patients is significant compared to CC and GG (P=0.007); The rate of hypertension was higher in IL1RN A3A3 and A2A2 polymorphisms in patients (P=0.031) and the incidence of HL was found to be higher in A3A3 and A1A1 polymorphisms (P=0.003).

Conclusions: The development of HT is multifactorial. In our study, it has been shown that TSHR, CTLA-4 and IL-1RN do not create a significant predisposition to HT. However, it should be taken into consideration that factors such as the diversity of polymorphisms, ethnic differences and the number of patients may affect the results and studies should be evaluated accordingly.