These results together indicate that transplantation with the ASPA iNPCs was able to rescue the deficiency of ASPA enzymatic activity and reduce NAA level, both of which are major defects in CD patients and mouse models, and that the therapeutic effect was resulted from the cell products instead of the procedure by itself because medium control exhibited no effect on either ASPA activity or NAA level. This evidence concerns the gene ASPA and Cowden disease.