Genetic variant rs623011 (17q24.3) associates with non-familial thyrotoxic and sporadic hypokalemic paralysis

Abstract

BackgroundA recent genome-wide association study of Thai patients with thyrotoxic periodic paralysis (TPP) identified a novel genetic variant rs623011 located in chromosome 17q24.3, which may potentially reduce the transcription of Kir2.1 and total Kir current. PurposeThe aim of this study was to evaluate whether this genetic variant was present in Chinese patients with TPP and sporadic periodic paralysis (SPP), the second leading cause of non-familial hypokalemic periodic paralysis (hypoKPP) in Asia. MethodsNinety patients with TPP, 61 SPP, and 100 age and sex-matched healthy subjects were performed. Genomic DNA was isolated from blood leukocytes and analysis of rs623011 was performed by polymerase chain reaction and direct sequencing. ResultsCompared with normal control, the frequency of the risk allele A of rs623011 was significantly higher in both TPP and SPP patients (73.9% versus 53.5%, p=0.001; 82.0% versus 53.5%, p<0.001, respectively) with the Odds ratios (95% confidence interval) 2.426 (1.348–4.369) and 4.488 (2.265–8.891), respectively. The frequency of the A allele of rs623011 was similar between TPP and SPP. ConclusionsTPP and SPP have the same susceptible gene variant rs623011 and may share the pathogenic mechanism of reduced Kir current in skeletal muscle independent of thyroid hormone.