Analysis of the KCNQ1 gene mutation in 2 families with congenital long QT syndrome type 1 in Xinjiang Uygur Autonomous Region

Objective Present study analyzed the association betwen the postassium voltage-gated channel KQT-like subfamily member 1 gene (KCNQ1) mutation and the clinical and the electrocardiographic features in 2 pedigrees with congenital long QT syndrome type 1 (LQT1) in Xinjiang Uygur Autonomous Region. Methods Three family members were diagnosed as LQT1 patients in 2 Uygur congenital LQT1 families, these 3 LQT1 patients served as long QT group, 24 Uygur healthy volunteers served as control group. Electrocardiogram (ECG) and the gene detection were applied to compare the ECG and molecular genetic features between the long QT group and control group, and to explore the relationship between the KCNQ1 gene mutation and the clinical and the electrocardiographic features in these 2 families with congenital long QT syndrome type 1. Results The LQT1 was diagnosed in 3 cases of the 2 pedigrees. The common features of ECG were QTc>480 ms, prolonged ST segment, and delayed T wave. The gene test evidenced a polymorphism of KCNQ1 gene exon 13:47G➝A(R16R). The mutation of 133G➝A9(G45S) of exon 16 resulted in the change of the original glycine (G) to serine (s). The ECG of the control group were normal, and there were no KCNQ1 gene mutations in control group. Conclusion The exon sequencing results of KCNQ1 gene in 2 Xinjiang Uygur congenital long LQT1 families showed that exon16 missense changes (133G to A (G45S)) can lead to amino acid mutation, this mutation may be a pathogenic mutation. Subsequent validation of the expanded sample will provide a reference for revealing the relationship between the KCNQ1 gene and the pathogenesis of LQT1. Key words: Genes; Mutation; Long QT syndrome