Genetic diagnosis in hypertrophic cardiomyopathy: two steps forward, one step back

• Published in: Cardiologia Hungarica (Budapest) 2021, Vol.51 (2), p.109-117
• Main Authors: Hategan, Lidia, Csányi, Beáta, Borbás, János, Pálinkás, Eszter Dalma, Takács, Hedvig, Nagy, Viktória, Sepp, Róbert
• Format: Article
• Language: English
• ISSN: 0133-5596; 1588-0230
• DOI: 10.26430/CHUNGARICA.2021.51.2.109

Hypertrophic cardiomyopathy (HCM) is the most common genetic cardiovascular disorder worldwide which exhibits considerable genetic heterogeneity. Widespread utilization of next-generation sequencing (NGS) in HCM has uncovered substantial genetic variation and highlighted the importance of a standardized approach to variant interpretation. According to this, accurate and consistent interpretation of sequence variants is essential for effective clinical care for individuals and their families with HCM. With this regard, the 2015 guidelines from the American College of Medical Genetics and Genomics and the Association for Molecular Pathology (ACMG/AMP) were widely applicable, but several elements lacked specificity for given genes or diseases. The latter guideline was adapted for the most frequent causative HCM gene, the beta myosin heavy chain gene (MYH7) by the ClinGen (Clinical Genome Resource) expert panel, the Inherited Cardiomyopathy Expert Panel. Due to the adaptation, the guideline became gene-specific, with general considerations which are widely adaptable for most of the causative genes in HCM. Based on the modified guideline, web-based interpretation algorithms have been developed which integrate data from population databases and define pathogenicity of different variants independent of the observer, therefore aiding standardized clinical interpretation of genetic testing. The latter approach serves as a basis for recommendation for genetic testing in the recent ACC/AHA HCM guideline published in 2020. The current review is meant to compile the latest advances in HCM genetic testing in clinical practice, while bringing into focus some of the ongoing challenges clinical geneticists are still facing. Although nowadays the interpretation of genetic findings is two steps closer to a more accurate approach due to gene adaptation and automatization, the multitude of putative causative genes have been once again reduced to the 8 sarcomere genes, a backward step.