Evaluation of the 2019 ACMG-ClinGen guidelines for interpretation of copy-number variants with borderline classifications at an academic clinical diagnostics laboratory

Copy-number variation is a source of both genetic diversity and Mendelian disease. Analysis of copy-number variants (CNVs) is an essential and frequently utilized component of medical genetics for a wide variety of patient indications. In 2019, the American College of Medical Genetics and Genomics (ACMG) and the Clinical Genome Resource (ClinGen) developed new technical standards for the interpretation of CNVs, introducing a semi-quantitative classification system that aims to foster greater standardization and consistency of classifications between laboratories.