For example, Pompe disease results from defective glycogen degradation that also impairs autophagic flux in muscle cells; Danon disease reflects abnormalities in the lysosome–autophagy interface due to LAMP2 deficiency; and the neuronal ceroid lipofuscinoses (NCLs) involve defective clearance of lipopigments with secondary mitochondrial dysfunction. The gene discussed is LAMP2; the disease is Danon disease.