Thyrotoxic periodic paralysis and polymorphisms of sodium-potassium ATPase genes

Abstract

Objective: Thyrotoxic periodic paralysis (TPP) is a complication of hyperthyroidism association with recurrent, reversible episodes of muscle weakness. Increased sodium-potassium ATPase (Na/K-ATPase) pump activity is postulated to contribute to the hypokalaemic paralytic attacks in TPP. The aim of this study was to determine the genetic predisposition to TPP in relation to Na/K-ATPase genes. Design: A case-control association study. Patients: Ninety-nine male Chinese TPP patients were compared to 84 male Graves' disease (GD) patients without TPP and 100 normal male controls. Measurement: A total of 1500 base pairs upstream of the transcriptional start site of the five Na/K-ATPase genes that are expressed in the skeletal muscles, namely ATP1A1, ATP1A2, ATP1B1, ATP1B2 and ATP1B4, were sequenced in all subjects for mutations or polymorphisms. The single nucleotide polymorphisms (SNPs) of the coding regions of the five genes were also studied for association with TPP. Results: No mutations were detected in the 5′ regions of the five genes in any of the patients studied. There was no difference in the distribution of SNPs and SNP haplotypes in the upstream and coding region of these genes between the three groups of subjects. Conclusion: No association between the polymorphisms of ATP1A1, ATP1A2, ATP1B1, ATP1B2 and ATP1B4 genes and TPP could be detected. © 2006 Blackwell Publishing Ltd.