Danon disease is a rare X-linked dominant lysosomal disease due to mutations in the lysosome associated membrane protein-2 (LAMP-2), is clinically characterised by hypertrophic cardiomyopathy, myopathy and mental retardation.Therefore, Danon disease usually was misdiagnosed and treated with hypertrophic cardiomyopathy (HCM) caused by mutations in genes encoding cardiac sarcomere proteins.Herein, we report a new case of Danon disease with HCM and ophthalmic abnormality that showed a new mutation in the LAMP-2 gene in a 17-year-old Chinese young child.