SCN5A GENE MUTATIONS AND RELATED FACTORS IN BRUGADA SYNDROME PATIENTS IN VIETNAM

Đặng Duy Phương1, Nguyễn Minh Hà2, Đỗ Doãn Lợi1,3, Trần Vân Khánh1, Trần Huy Thịnh1,
1 Hanoi Medical University
2 Pham Ngoc Thach University of Medicine, Ho Chi Minh City
3 Vietnam National Heart Institute

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Abstract

Introduction: Brugada syndrome is an inherited cardiac arrhythmia that causes sudden death. Mutations in SCN5A gene, which codes for sodium channels, have been identified as the cause and account for the highest frequency, about 20-25% in the Brugada syndrome (BrS) patients. The lack of relevant information about the clinical, subclinical characteristics and SCN5A mutation status in Vietnam has partly limited the quality of care as well as the implementation of studies to improve the effectiveness of disease pathology management.  Objectives: To investigate the frequency of mutations in SCN5A gene and its association with some clinical and subclinical characteristics in BrS patients. Subjects and methods: using the case series study to survey on clinical, subclinical characteristics and mutation frequency of SCN5A gene in BrS patients in hospitals in Ho Chi Minh City and Hanoi. To comment on the relationship between traits and gene mutations found. The disease was diagnosed according to the European Heart Rhythm Society 2015 criteria. Mutations were identified by Sanger sequencing technique. Results: There were 70 patients participating in the study. SCN5A mutation frequency is 25,7%, including 13 types of mutations, of which 7 types have been published in the literature. 80% is a missense mutation; mutations are concentrated in the transmembrane regions (42,1%) and transmembrane linkers (36,8%) on the protein. When predicting pathogenicity by multiple bioinformatic tools, there are 53,8% pathogenic mutations; 30,8% likely pathogenic mutations. There are the SCN5A mutation-positive group with more patients with sudden death of a relative under 45 years old than the mutation-negative group (p=0,029); who has a higher rate of ventricular arrhythmias (p=0.049); with a higher rate of positive flecanide test than the mutation-negative group (p=0,034). There may be an association between SCN5A mutation status and family factors of sudden death under 45 years old (OR 8,4; p = 0,0005); and with a positive result of the flecanide test (OR 7,1; p = 0,032). Conclusion: The SCN5A mutation frequency in BrS patients in Vietnam has been determined, and 5 new types of mutations have not been published on biological databases. The study also gives initial hints about the association between some clinical and subclinical features with SCN5A gene mutations in BrS patients.

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References

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