The purpose of this study is to obtain information pertaining to the occurrence of antibodies
to investigational SPK-3006 and GAA, GAA activity and GAA antigen levels in the usual care
setting of Late-Onset Pompe Disease (LOPD) participants on an enzyme replacement regimen.
Additionally, a careful evaluation of laboratory and functional testing in patients with LOPD
may provide information to better understand the disease features and better drive the design
of a future interventional investigational gene therapy trial. An understanding of the
underlying status of liver and muscle health in individuals with LOPD may also inform best
surveillance during the conduct of gene therapy trials.