This study is for children ages 0 to under 18 with a rare condition called **Infantile-onset Pompe Disease (IOPD)**. IOPD is a genetic disorder that affects the heart and muscles. The study tests a treatment using **cipaglucosidase alfa/miglustat** to see how safe and effective it is. Some kids have already taken a different treatment called **Enzyme Replacement Therapy (ERT)**, while others haven't.

Key Points:

• The study is 104 weeks (about 2 years) long, and kids will have to visit a clinic multiple times.
• Participants must have specific health conditions, like heart problems, and must be able to walk a certain distance.
• Kiddos should not have a history of serious reactions to similar therapies or be on certain ventilators.

Doctors will look at how the medicine moves in the body (PK), how it affects the body (PD), and if it causes any immune reactions (immunogenicity). This helps understand if the treatment works and is safe. Participants should talk with their doctors and families to decide if joining this study is right for them.