For Pompe disease, for which clinical trials combining ERT and treatment with NB-DNJ and DNJ have recently been concluded28,35, PCT is particularly promising as pharmacological chaperones are small molecules that are expected to penetrate membranes and reach therapeutic levels in target tissues, including skeletal muscle (38–55% of human body weight), more easily than rhGAA. This evidence concerns the gene ELF3 and glycogen storage disease II.