A one-time treatment can put a missing gene into a child’s body so their cells make an enzyme that used to be missing.

Put the working gene in once. Cells make the enzyme that used to be missing. Harmful sugar buildup can fall. Family daily life can change — schedules, school plans, caregiving load — when a disease-modifying option exists.

Specialized care and monitoring still belong in the story. The one idea is the mechanism, not a promise that every skill returns overnight for every child.