The present invention provides a method for increasing the activity of a mutant or wild-type α-glucosidase enzyme in vitro and in vivo by contacting the enzyme with a specific pharmacological chaperone which is a derivative of 1- deoxynojirimycin. The invention also provides a method for the treatment of Pompe disease by administration of chaperone small molecule compound which is a derivative of 1-deoxynojirimycin. The 1-deoxynojirimycin derivative is substituted at the N or Cl position. Combination therapy with replacement α-glucosidase gene or enzyme is also provided.
