For instance, we identified 2 patients below the age of 30, with rare HCM phenocopies: Danon disease and Fabry disease due to pathogenic variants in the LAMP2 (HGNC:6501, NM_002294.3) gene and GLA (HGNC:4296, NM_000169.2) gene, respectively. This evidence concerns the gene LAMP2 and Fabry disease.