A Prospective Study to Observe & Describe Clinical Outcomes of Alglucosidase Alfa Treatment in Patients ≤6 Months of Age With Infantile-onset Pompe Disease (IOPD)

Inclusion Criteria:

• At the time of informed consent, participants must be ≤6 months of age, correctedfor gestation if necessary. Gestational age <40 weeks will be adjusted to afull-term gestational age of 40 weeks.

• Participants must have alglucosidase alfa enzyme replacement therapy (ERT) plannedor initiated for IOPD treatment irrespective of study participation, according tothe treating physician's decision regarding participants' routine diseasemanagement.

• Participants must have available and accessible medical records from the time ofIOPD diagnosis and from subsequent follow-up.

• Participants must have a confirmed diagnosis of IOPD, defined as presence of 2pathogenic acid alpha glucosidase (GAA) variants and documented GAA deficiency inblood (dried blood spot [DBS] accepted), skin, or muscle tissue, or presence of 1pathogenic GAA variant and documented GAA deficiency in blood, skin, or muscletissue from separate samples (either from 2 different tissues or from the sametissue but at 2 different sampling dates.) (DBS and leukocytes are acceptable as 2different samples from blood).

• Participants must have established cross-reacting immunologic material (CRIM) statusavailable prior to enrollment. CRIM status may be provided by historical CRIMtesting results or prediction of CRIM status based on genotyping performed at aClinical Laboratory Improvement Amendments (CLIA) or other appropriately certifiedgenetic laboratory.

• Participants must have cardiomyopathy at the time of diagnosis (LVMI equivalent tomean age-specific LVMI):

• LVMI +1 standard deviation (SD) in participants diagnosed by newborn or siblingscreening,

• LVMI +2 SD in participants diagnosed by clinical evaluation.

• Participants must have informed consent provided by parent(s)/legally acceptablerepresentatives (LARs).

Exclusion Criteria:

• Participants with respiratory insufficiency, defined as:

• Oxygen saturation <90% on room air as determined by pulse oximetry,

• Venous partial pressure of carbon dioxide (pCO2) >55 mmHg or arterial pCO2 >40mmHg on room air,

• Use of invasive (with intubation or tracheostomy) or noninvasive (no intubationor tracheostomy) ventilation at enrollment, for participants not having startedERT at enrollment,

• Use of invasive or noninvasive ventilation at the time of ERT initiation, forparticipants having started ERT before enrollment.

• Participants with major congenital abnormality including heart defect, neural tubedefect, or Down syndrome that, in the opinion of the investigator, would precludeparticipation in the study or potentially decrease survival.

• Participants with clinically significant organic disease other than signs/symptomsrelated to Pompe disease, including clinically significant cardiovascular, hepatic,pulmonary, neurologic, or renal disease, or other medical condition, seriousintercurrent illness, or circumstance that, in the opinion of the investigator,would preclude participation or potentially decrease survival.

• Previous or ongoing treatment in any clinical trial of, or managed access programfor, avalglucosidase alfa or any other Pompe disease-specific therapy.

The above information is not intended to contain all considerations relevant to a patient's potential participation in a clinical trial.