The ClinGen Inherited Cardiomyopathy Expert Panel (CMP-EP) has entered into a formal affiliation with the United Kingdom’s Association for Clinical Genomic Science (ACGS). They will be working jointly to adapt the ACMG/AMP variant classification guidelines for genes associated with hypertrophic cardiomyopathy (HCM). This work is an extension of the ClinGen CMP-EP’s recommendations for MYH7 variant classification. ClinGen and ACGS have a shared goal of developing standardized genomic variant interpretation guidelines for improved patient care. The contribution of genomic and phenotypic data from both groups, as well as collaboration in the decision-making process, represents a first step in global development, acceptance, and use of a common set of specified guidelines.