Analysis of DSG2, TTN and GATA4 gene variants in patients with Brugada syndrome from Henan / 中华医学遗传学杂志

OBJECTIVE@#To explore the correlation between DSG2, TTN and GATA4 genes and Brugada syndrome in Henan Province of China.@*METHODS@#From February 2017 to February 2019, 100 patients with Brugada syndrome and 100 healthy individuals were selected as the study and the control groups, respectively. Electrocardiogram and echocardiography were carried out, and peripheral blood samples was collected. Coding regions of DSG2, TTN and GATA4 genes were amplified by PCR and sequenced. The results were compared with standard sequences from GenBank.@*RESULTS@#Electrocardiogram showed that all patients from the study group had ventricular arrhythmia, 87 cases (87%) presented ventricular tachycardia (VT), 84 cases (84%) presented T wave inversion, and 51 cases (51%) presented Epsilon wave. Echocardiography showed that the right ventricle in the study group was enlarged with the inner diameter of the right ventricle being (40.0±13.3) mm, and the right ventricle showed various degree of abnormal systolic function. The enlargement of right atrium accounted for 64%, and the involvement of the left ventricle accounted for 27%. The right ventricular diameter and left ventricular diastolic diameter of the study group were significantly greater than those of the control group (P< 0.05). DNA sequencing showed that 60 patients carried DSG2 gene variants, among which 18 had missense variant of exon 8. Fifty patients carried TTN gene variants, including 8 in the A-band domain and 3 in the I-band domain. Twenty patients carried 3 variants of the GATA4 gene.@*CONCLUSION@#Variants of the DSG2, TTN and GATA4 genes in Henan region are correlated with the onset of Brugada syndrome.

Compound Heterozygous SCN5A Mutations in a Toddler - Are they Associated with a More Severe Phenotype? / Heterozigose Composta no Gene SCN5A em Criança - Há Associação com Gravidade da Doença?

Abstract Compound heterozygosity has been described in inherited arrhythmias, and usually associated with a more severe phenotype. Reports of this occurrence in Brugada syndrome patients are still rare. We report a study of genotype-phenotype correlation after the identification of new variants by genetic testing. We describe the case of an affected child with a combination of two different likely pathogenic SCN5A variants, presenting sinus node dysfunction, flutter and atrial fibrillation, prolonged HV interval, spontaneous type 1 Brugada pattern in the prepubescent age and familiar history of sudden death.

Resumo A heterozigose composta é descrita em arritmias hereditárias, geralmente associada a um fenótipo mais grave. Relatos dessa ocorrência em pacientes com síndrome de Brugada ainda são raros. Neste estudo, descrevemos o caso de uma criança com a combinação de duas novas variantes distintas no gene SCN5A, apresentando disfunção do nó sinusal, flutter e fibrilação atrial, intervalo HV prolongado, padrão tipo 1 espontâneo de Brugada na idade pré-puberal e história familiar de morte súbita.

Brugada syndrome and its relevance in the perioperative period.

Brugada syndrome is an autosomal dominant genetic disorder associated with an increased risk of sudden cardiac death, as well as ventricular tachyarrhythmias.The defective cardiac sodium channels result in usual electrocardiographic findings of a coved-type ST elevation in precordial leads V1 to V3. The majority of patients have uncomplicated courses with anesthesia, surgery, and invasive procedures. However there is risk of worsening ST elevation and ventricular arrhythmias due to perioperative medications, surgical insult, electrolyte abnormalities, fever, autonomic nervous system tone, as well as other perturbations. Given the increasing numbers of patients with inherited conduction disorders presenting for non-cardiac surgery that are at risk of sudden cardiac death, safe anesthetic management depends upon a detailed knowledge of these conditions.

Molecular Genetic Analysis of One Sudden Unexplained Death in the Young by Whole Exome Sequencing / 法医学杂志

OBJECTIVE@#To find the mutation of disease-causing genes of sudden unexplained death syndrome (SUDS) in the young by whole exome sequencing in one case.@*METHODS@#One SUDS case was found no obvious fatal pathological changes after conventional autopsy and pathological examination. The whole exome sequencing was performed with the Ion Torrent PGM™ System with hg19 as reference sequence for sequencing data. The functions of mutations were analyzed by PhyloP, PolyPhen2 and SIFT. A three-step bioinformatics filtering procedure was carried out to identify possible significative single nucleotide variation (SNV), which was missense mutation with allele frequency < 1% of myocardial cell.@*RESULTS@#Four rare suspicious pathogenic SNV were identified. Combined with the analysis of conventional autopsy and pathological examination, the mutation MYOM2 (8_2054058_G/A) was assessed as high-risk deleterious mutation by PolyPhen2 and SIFT, respectively.@*CONCLUSION@#Based on the second generation sequencing technology, analysis of whole exome sequencing can be a new method for the death cause investigation of SUDS. The gene MYOM2 is a new candidate SUDS pathogenic gene for mechanism research.

Bases genéticas y moleculares del síndrome de Brugada mediado por canales de sodio / Genetic and molecular basis for sodium channel-mediated Brugada syndrome

El síndrome de Brugada es una enfermedad hereditaria caracterizada por una anormalidad electrocardiográfica y un aumento del riesgo de muerte súbita cardiaca. El síndrome de Brugada puede ser causado por la presencia de mutaciones en el gen SCN5A en aproximadamente el 20% de los casos familiares. El gen SCN5A codifica la subunidad a del canal iónico de sodio en las células cardiacas. Estudios realizados durante la última década en genética molecular han permitido identificar 11 nuevos genes con susceptibilidad para síndrome de Brugada además del SCN5A, lo que lleva a pensar que es una enfermedad con heterogeneidad genética y compleja de identificar en la clínica y a nivel molecular en el laboratorio. Una manera de heredar el síndrome de Brugada es por medio de un patrón de transmisión hereditaria autosómica dominante. Esta breve revisión se enfoca a describir el proceso de diagnóstico de marcadores genéticos en un caso reportado de síndrome de Brugada guiando al lector a través del proceso de identificación de las variantes genéticas responsables del síndrome y a determinar la consecuencia funcional de las mutaciones del canal de sodio sobre la alteración electrocardiográfica.

Brugada syndrome is a genetic disease that is characterized by abnormal electrocardiogram findings and an increased risk of sudden cardiac death. This syndrome is linked to mutations in the SCN5A gene in approximately 20% of Brugada syndrome probands. SCN5A encodes the a subunit of the cardiac sodium channel. Studies conducted over the past decade have identified 11 other Brugada syndrome susceptibility genes besides to SCN5A, pointing to genetic heterogeneity of the syndrome. Transmission of the disease shows an autosomal dominant inheritance pattern. This brief review focuses on a reported case of sodium channel-mediated Brugada syndrome, guiding the reader through the process of identification of the genetic variants responsible for the clinically-diagnosed syndrome, mutagenesis to clone SCN5A with and without the 2 variants identified and transfection of the 2 variants into TSA201 cells to determine the functional consequence of these genetic variants on sodium channel expression and function.

Postmortem genetic testing in sudden cardiac death due to ion channelopathies / 法医学杂志

Sudden cardiac death accounts for majority of deaths in human. Evident cardiac lesions that may explain the cause of death can be detected in comprehensive postmortem investigation in most sudden cardiac death. However, no cardiac morphological abnormality is found in a considerable number of cases although the death is highly suspected from cardiac anomaly. With the advances in the modern molecular biology techniques, it has been discovered that many of these sudden deaths are caused by congenital ion channelopathies in myocardial cell, i.e., Brugada syndrome, long QT syndrome, catecholaminergic polymorphic ventricular tachycardia, and short QT syndrome, etc. This article presents the molecular genetics, electrocardiographic abnormalities, clinical manifestations, and mechanisms leading to sudden cardiac death with emphasis on the role of postmortem genetic testing in certification of cause of death. It may provide helpful information in investigating sudden cardiac death due to ion channelopathies in medico-legal practice.

Brugada syndrome and anaesthesia A case report and review

Brugada Syndrome is an inherited form of cardiac disease characterized by arrhythmias and sudden death with a prevalence of 5 per 10.000. Although this condition is estimated to be responsible for 4%-12% of all sudden deaths in the general population, it is not commonly recognized because of limited reports in the literature. The Brugada syndrome is an increasingly recognized disorder and anaesthetists are likely to encounter this syndrome in practice, this review is to find out the implications of Brugada syndrome for anaesthesia and to outline recommendations for per operative anaesthetic management. We present a forty years old female who was successfully resuscitated after a community [ventricular fibrillation] VF arrest. The diagnosis Brugada Syndrome was confirmed with a flecainide provocation test and treated by insertion of an implantable defibrillator [ICD]. Two years later she had another VF arrest which was terminated by the implantable defibrillator [ICD]. In recent years [2000- 2006] less than two dozen cases have been reported, we reviewed published papers written in English language using journals and internet, using the wards anaesthesia and Brugada Syndrome. Drugs that are known triggers [e.g. class-IA and IC anti-arrhythmic drugs] should be avoided. Similarly, conditions that may provoke Brugada ECG like changes [e.g. hyper-and hypokalaemia, hypercalcaemia and hyperthermia] should be avoided. Implantation of ICD is currently the only proven effective therapy. Known patients of Brugada syndrome without an ICD should have external defibrillator paddles attached before commencing anaesthesia. Postoperative monitoring for 36-48 h is highly recommended as cardiac arrhythmias can occur during this time. This is particularly important when continuous infusions of local anaesthetic drug are used for regional blockade. Liaison with a cardiologist for both preoperative preparations and future follow-up improves outcome. The Brugada Syndrome should be excluded in patients with a family history of unexplained sudden death and in those with typical ST segment changes on ECG. Due to limited number of reports, the implications for anaesthesia are limited and it is difficult to draw firm conclusions