Genetic Analysis of SCN5A Gene in Patients of Long QT Syndrome

Uzma Zaheen, Memona Yasmin, Saadia Noreen, Saqib Ali, Allah Rakha


Background: Finding out the cause of death is the main concern in forensic casework, particularly in sudden unexplained death cases. Long QT syndrome is a form of life debilitating cardiac arrhythmia. Among LQT genes, LQT3 is suggested to be more lethal and patients are at high probability of sudden death as compared to LQT1 and LQT2 patient.

Methods: Samples of long QT patients were collected and the coding regions of all exons of the SCN5A, voltage- gated Na+ channel gene were screened by sequencing for the potential mutations as the causative agent of long QT syndrome.

Results: After data analysis, 3 genetic variations have been found, amongst them are 2 heterozygous mutations that were reported previously in other ethnicity G87A-A29A found in exon 2, G1673A-H558R in exon 12 and one novel mutation that has not been reported so far, G>A 1238-G412G resulting in a transition mutation and change in amino acid GGG- Glycine to GAG- glutamic acid at position 412 in exon 9. While in other exons, no significant mutation was found.

Conclusion: As some of the exons showed mutation and the sample size was small, however, further functional analysis of the gene is needed with large number of samples for the confirmation of results.

Keywords: Long QT Syndrome; SCN5A gene; Genetic variations; Sudden death

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