TSHR and thyrotoxic periodic paralysis: This man was diagnosed with Graves’ disease in February 2002 when he presented with thyrotoxic periodic paralysis associated with severe hypokalemia (plasma potassium = 1.8 mmol/L) due to transcellular potassium shift precipitated by hyperthyroxinemia.His initial TSH receptor antibody (TRAb) level was 9.7 U/L.