LAMP2 and Danon disease: In patients with clinically suspect of Danon disease or unexplained LV hypertrophy, the diagnosis is supported by the presence of normal acid maltase levels on muscle biopsy, the deficiency of LAMP2 protein by immunohistochemistry, the evidence of autophagic vacuole accumulation by microscopy, and the presence of a disease-causing mutation of LAMP2 (97).