Technological advances have allowed us to more comprehensively and efficiently interrogate human genomes, and there are a number of large-scale efforts, such as the Exome Sequencing Project and Exome Aggregation Consortium, which have been publishing genomic data and variant frequencies from very large populations stratified by ethnicity. Utilizing our criteria for variant classification, which is largely on the basis of the American College of Medical Genetics and Genomics and the Association for Molecular Pathology 2015 guidelines for variant interpretation (4) and utilizes databases and resources listed in the preceding text, only 6 of these variants could be confidently classified as likely pathogenic or pathogenic (i.e., 6 of 3,600, or approximately 1:600 HCM gene carrier frequency).