HLA-B*39:01:01 is a novel risk factor for antithyroid drug-induced agranulocytosis in Japanese population

First Case Report of Arrhythmogenic Right Ventricular Cardiomyopathy Showing Refractory Ventricular Tachycardia Induced by Thyroid Storm due to Graves’ Disease

A 48-year-old man who was diagnosed with arrhythmogenic right ventricular cardiomyopathy (ARVC) due to a plakophilin 2 gene mutation developed acute both-sided heart failure with rapid atrial fibrillation and was hospitalized. After admission, sustained ventricular tachycardia, which was refractory to antiarrhythmic agents, occurred repeatedly, and required electrical cardioversion. He was diagnosed with thyroid storm due to Graves' disease, and treatment for hyperthyroidism was initiated. After the treatment, lethal arrhythmia did not reoccur, and biventricular heart failure ameliorated. To our best knowledge, this is the first report in English of a patient with ARVC showing refractory arrhythmia induced by thyroid storm due to Graves' disease.

A case of methimazole-induced acute pancreatitis with an HLA allele causing antithyroid drug-induced agranulocytosis

Among the side effects of methimazole (MMI) for the treatment of Graves’ disease, MMI-induced acute pancreatitis (MIP) is a rare adverse reaction, with only 7 cases being reported to date. However, 2 large-scale population-based studies recently revealed that the risk of MIP was significantly higher, ranging from 0.02% to 0.56%. Although MIP is common in middle-aged and elderly Asian women, its pathogenesis remains largely unknown. We herein present a case of a 72-year-old Japanese woman with Graves’ disease who developed MIP 12 days after the initiation of MMI. The MMI was discontinued, the patient was switched to propylthiouracil (PTU) therapy, and pancreatitis gradually resolved. Serological human leukocyte antigen (HLA) typing identified HLA-DRB1*08:03:02. This HLA allele was previously detected in a patient with MIP and is one of the major risk factors for agranulocytosis induced by antithyroid drugs, including PTU as well as MMI. In cases of MIP, PTU is being considered as an alternative to MMI; however, its safety needs further investigation and patients require close monitoring after the switch to PTU. Further studies are warranted, particularly on the relationship between MIP and the presence of HLA alleles causing antithyroid drug-induced agranulocytosis.