This is a clinical study to evaluate the safety and efficacy of gene therapy drug SKG0201 Injection in patients with spinal muscular atrophy Type 1 (SMA 1).

This is a multicenter, open, dose-escalation clinical study to evaluate the safety, initial efficacy, and immunogenicity of SKG0201 injection in patients with spinal muscular atrophy type 1 (SMA 1).

Inclusion Criteria:

1. Type 1 SMA, defined by bi-allelic mutations in the SMN1 gene.
2. Age 180 days or younger at day of infusion.
3. Clinical history and signs are consistent with type I SMA, that is hypotonia on clinical examination, with delay in motor skills, poor head control, rounded shoulder posture, and joint hypermobility.
4. The legal guardian of the subject understands the purpose of the study, the possible risks and rights of the study, agrees that the subject can participate in the study, complete all research steps, tests and visits, and sign the ICF voluntarily.
5. During the study period, according to the change of the subject's condition, the subject's legal guardian is willing to perform standard treatment requirements as suggested by the researcher.

Exclusion Criteria:

1. Pulse oximetry < 96% saturation at screening while the patient is awake or asleep without any supplemental oxygen or respiratory support.
2. Weight-for-age below the 3rd percentile for the same sex and age based on WHO Child Growth Standards (WHO 2006).
3. Active viral infection with significant signs or symptoms and require systematic hospitalization.
4. In the presence of other severe infections or diseases.
5. Known allergy to prednisolone, other glucocorticoids, or their excipients.
6. Clinically significant abnormal laboratory values prior to administration.
7. Previously used other SMA drugs (such as Spinraza, Evrysdi, Zolgensma, etc.) or participated in clinical studies of other SMA drugs.
8. Had received previous or anticipated major surgical procedures during the study assessment period.