Subjects exposed to gene therapy products (GTPs) may be at risk for delayed or long-term adverse events. This is a long-term follow-up (LTFU) protocol designed to evaluate the long-term safety of Seattle Children's Therapeutics (SCTx) GTPs and incorporates in monitoring guidance from the U.S. Food and Drug Administration (FDA). Subjects will be followed for up to 15 years starting from the date of the most recent infusion of an SCTx GTP. Subjects planning to receive, or who have received, at least one infusion of an SCTx GTP will be offered participation in this LTFU study. Subjects enrolled in this study will have safety assessments and laboratory evaluations performed at scheduled intervals for each unique SCTx GTP received. No treatment is administered in this LTFU study.

Inclusion Criteria:

1. Enrolled in an SCTx GTP clinical trial;
2. Received or planned to receive an SCTx GTP;
3. Subject and/or legally authorized representative have provided consent/assent for study participation.

Patients who have received treatment with a gene therapy product on an SCTx Sponsored clinical trial.