Alglucosidase Alfa Temporary Access Program

Inclusion Criteria: * The patient or patient's legal guardian must provide signed, informed consent prior to performing any study-related procedures. * The patient must reside in the US. * The patient must have a confirmed diagnosis of Pompe disease defined as documented acid alpha-glucosidase (GAA) enzyme deficiency from any tissue source and/or GAA gene mutations. * The patient must have/had documented clinical signs and symptoms of Pompe disease. * The patient must have/had prior treatment with alglucosidase alfa produced at commercial scale OR be naive to enzyme replacement therapy (ERT) for the treatment of Pompe disease and meet at least 1 of the following criteria: require a wheelchair OR require some respiratory assistance for any number of hours (including night time) through non-invasive ventilation. * The patient must be capable of complying with the required program schedule of assessments. Exclusion Criteria: * Females who are pregnant or lactating * The patient has a clinical condition unrelated to Pompe disease that would interfere with program assessments. * The patient is currently enrolled in any clinical studies.