• Subject's parent or legal guardian has provided signed eICF.

• Subject with SMA, genetically confirmed: with a bi-allelic mutation in the SMN1 gene, and a clinical diagnosis of SMA Type 1 or up to 3 copies of the SMN2 gene.

• Subject treated\* with Onasemnogene Abeparvovec (Zolgensma®) prior to enrolling in this study.

⁃ Subjects treated with nusinersen or risdiplam prior to Onasemnogene Abeparvovec (Zolgensma®) can be enrolled if currently not receiving it.

⁃ \*Subjects can be enrolled in this study on the day treated with Onasemnogene Abeparvovec (Zolgensma®) or if prior medical history is available to complete all assessments retrospectively, in accordance with local ethical requirements.

• Subject and parent/guardian are willing and able to comply with the phone contacts through the course of the study