LAMP2 and Danon disease: Danon disease, caused by the mutations in the gene of lysosome‐associated membrane protein 2 (LAMP2,OMIM*309060), is an X‐linked dominant disorder classically characterized by the triad of cardiomyopathy, skeletal myopathy, and intellectual disability (Danon et al., 1981; Nishino et al., 2000; Tanaka et al., 2000).