No mutation in the KCNE3 potassium channel gene in Chinese thyrotoxic hypokalaemic periodic paralysis patients

Summary objectives  Mutation in KCNE3 gene (Isk-related family potassium voltage-gated channel member 3 gene) was recently associated with the aetiology of thyrotoxic periodic paralysis (TPP). We studied 79 Chinese TPP patients by DNA sequencing of the entire coding sequence of KCNE3 to determine if this gene is the cause of TPP in Chinese patients. design and measurements  A case–control genetic association study was carried out to determine the role of mutation/polymorphism in KCNE3 gene in the pathogenesis of TPP. Genomic DNA was extracted from peripheral blood samples. DNA sequencing was performed to cover the coding region of the KCNE3 gene for the TPP subjects. Restriction fragment length polymorphism was used to genotype specific sequence variants. subjects  Seventy-nine TPP patients (cases) and 111 male thyrotoxic patients without history of paralysis (controls) were identified from thyroid clinic and during acute admission in a teaching hospital. results  No pathogenic mutation in KCNE3 was found in the TPP patients. The reported R83H mutation was also not found in the Chinese TPP patients. In addition, another silent polymorphism, 290T/C, was also not associated with TPP. conclusion  The results indicate that mutation in KCNE3 is not a cause of TPP in Chinese patients.