Inclusion Criteria:  Signed, informed consent obtained prior to being enrolled into the study and prior to starting any data collection. Consent of a legally authorized guardian is required for legally minor patients as defined by local regulation. If the patient is legally minor, signed written consent shall be obtained from parent(s)/legal guardian and assent obtained from the patient, if applicable. Pompe disease patients with confirmed acid alpha-glucosidase (GAA) enzyme deficiency treated with Myozyme® in home infusion setting according to authorized clinical practice and the approved risk management plan document (Cohort A) or MPS I patients with confirmed deficiency of the lysosomal enzyme, alpha-L-iduronidase treated with Aldurazyme® in home infusion setting according to authorized clinical practice and the approved risk management plan document (Cohort B).  Exclusion Criteria:  Participation in another clinical trial with any investigational agent within the 12 weeks preceding enrolment. Any condition (e.g. medical concern) which, in the opinion of the Investigator, would make the participant unsuitable for the study.  The above information is not intended to contain all considerations relevant to a potential participation in a clinical trial.