Thyrotropin receptor antibodies and a genetic hint in antithyroid drug-induced adverse drug reactions.

Background: Antithyroid drugs (ATDs) are known to cause various adverse drug reactions (ADRs) that can lead to treatment complexity and unpredictable risks. With the aim of ensuring safer drug use, we assessed whether thyrotropin receptor antibody (TRAb) titers are associated with ATD-induced cutaneous reactions and/or hepatotoxicity, and examined potential genetic predisposition factors. Methods: We compared TRAb titers of 37 Graves' disease (GD) patients who had experienced carbimazole/methimazole-induced cutaneous reactions and/or hepatotoxicity with those of 40 normal individuals, or 78 GD patients without the aforementioned ATD-induced ADRs. We performed a genome-wide association study and/or human leukocyte antigen genotyping on GD patients [first stage (chart reviews): 24 cases with ADRs and 423 controls; second stage (actively recruited): 45 cases with ADRs and 137 controls]. Results: For patients with Graves' hyperthyroidism, individuals with higher TRAb titers showed a predisposition to carbimazole/methimazole-induced cutaneous reactions and/or hepatotoxicity, with an estimated odds ratio of 5.19 (cut-off value: 64%). Potential associations with the rs144542704 and rs61893841 on chromosomes 17 and 11, respectively, warrant further genetic association analysis. Conclusion: Our findings support the use of carbimazole/methimazole in patients with low TRAb titers to ensure safer drug use. The identified genetic associations warrant further research.