For example, the PubMed search used the Boolean structure, which was as follows: (“thyrotoxic periodic paralysis” OR “thyrotoxic hypokalemic periodic paralysis” OR “hypokalemic periodic paralysis”)AND (hyperthyroidism OR “Graves disease” OR thyrotoxicosis)AND (arrhythmia OR “beta-blocker” OR KCNJ18 OR Kir2.6)AND (Qatar OR “Saudi Arabia” OR Oman OR Bahrain OR “United Arab Emirates” OR Kuwait). This evidence concerns the gene KCNJ18 and periodic paralysis.