Identification and in-silico characterization of splice-site variants from a large cardiogenetic national registry.

Splice-site variants in cardiac genes may predispose carriers to potentially lethal arrhythmias. To investigate, we screened 1315 probands and first-degree relatives enrolled in the Canadian Hearts in Rhythm Organization (HiRO) registry. 10% (134/1315) of patients in the HiRO registry carry variants within 10 base-pairs of the intron-exon boundary with 78% (104/134) otherwise genotype negative. These 134 probands were carriers of 57 unique variants. For each variant, American College of Medical Genetics and Genomics (ACMG) classification was revisited based on consensus between nine in silico tools. Due in part to the in silico algorithms, seven variants were reclassified from the original report, with the majority (6/7) downgraded. Our analyses predicted 53% (30/57) of variants to be likely/pathogenic. For the 57 variants, an average of 9 tools were able to score variants within splice sites, while 6.5 tools responded for variants outside these sites. With likely/pathogenic classification considered a positive outcome, the ACMG classification was used to calculate sensitivity/specificity of each tool. Among these, Combined Annotation Dependent Depletion (CADD) had good sensitivity (93%) and the highest response rate (131/134, 98%), dbscSNV was also sensitive (97%), and SpliceAI was the most specific (64%) tool. Splice variants remain an important consideration in gene elusive inherited arrhythmia syndromes. Screening for intronic variants, even when restricted to the ±10 positions as performed here may improve genetic testing yield. We compare 9 freely available in silico tools and provide recommendations regarding their predictive capabilities. Moreover, we highlight several novel cardiomyopathy-associated variants which merit further study.

Return of Results Policies for Genomic Research: Current Practices and the Hearts in Rhythm Organization (HiRO) Approach.

Research teams developing biobanks and/or genomic databases must develop policies for the disclosure and reporting of potentially actionable genomic results to research participants. Currently, a broad range of approaches to the return of results exist, with some studies opting for nondisclosure of research results and others following clinical guidelines for the return of potentially actionable findings from sequencing. In this review, we describe current practices and highlight decisions a research team must make when designing a return of results policy, from informed consent to disclosure practices and clinical validation options. The unique challenges of returning incidental findings in cardiac genes, including reduced penetrance and the lack of clinical screening standards for phenotype-negative individuals, are discussed. Finally, the National Hearts in Rhythm Organisation (HiRO) Registry approach is described to provide a rationale for the selective return of field-specific variants to those participating in disease-specific research. Our goal is to provide researchers with a resource when developing a return of results policy tailored for their research program, based on unique factors related to study design, research team composition, and availability of clinical resources.

Arrhythmic Mitral Valve Prolapse and Mitral Annulus Disjunction in Heritable Aortic Disease.

Patients with heritable aortic disease (HAD) have an increased risk of ventricular arrhythmias and sudden cardiac death. Although mitral valve prolapse is common in HAD, mitral annulus disjunction (MAD) has only recently been described in these patients. This under-recognized condition may be a contributing factor to otherwise unexplained ventricular arrhythmias and sudden cardiac death in patients with HAD. This case series describes 3 patients in an adult HAD clinic who have concomitant mitral valve prolapse, MAD, and malignant arrhythmias. These cases may represent a unique disease entity or overlap syndrome, and they introduce MAD as a potential arrhythmogenic risk marker in HAD.

Les patients atteints de maladie aortique héréditaire (MAH) présentent un risque accru d'arythmie ventriculaire et de mort subite d'origine cardiaque. Bien que le prolapsus valvulaire mitral soit fréquent dans les cas de MAH, la disjonction annulaire mitrale (DAM) n'a été décrite que récemment chez ces patients. Cet état méconnu peut être un facteur contribuant à des arythmies ventriculaires autrement inexpliquées et à la mort subite d'origine cardiaque chez les patients atteints de MAH. Cette série de cas décrit trois patients d'une clinique de MAH pour adultes qui présentent un prolapsus valvulaire mitral, une DAM et des arythmies malignes en concomitance. Ces cas peuvent représenter une entité morbide unique ou un syndrome de chevauchement, et laissent entendre que la DAM pourrait être un nouveau marqueur du risque arythmogène associé à la MAH.