High-Throughput Methods for Variant Functional Assessment in Cardiac Disease

In vitro functional modeling of genetic variants has revolutionized our understanding of which variants can cause cardiac disorders, providing insights into their molecular underpinnings. This review provides an overview of high-throughput methods used for the functional assessment of variants implicated in inherited cardiac diseases. Advances in gene-editing technology now enable the efficient generation of cells expressing individual genetic variants or libraries of variants for robust functional studies. We discuss innovative assays that can evaluate dozens or hundreds of variants sequentially. For example, the electrophysiological properties of numerous cardiac ion channel variants in genes linked to inherited arrhythmias can be characterized using automated patch clamping. The mechanical properties of cardiomyocytes expressing candidate cardiomyopathy variants can be assessed using techniques such as atomic force microscopy, traction force microscopy, and impedance-based methods. Multiplexed assays of variant effect are an emerging family of techniques that use gene-specific or general assays, combined with next-generation sequencing, to characterize hundreds or thousands of pooled genetic variants. We examine the key advantages and limitations of each method and outline future goals for the field. Innovative in vitro studies of cardiac genetic variants will enhance our understanding of variant-disease relationships and improve diagnosis, screening, and treatment options for these disorders.