Study Overview: This study is testing a new treatment called DFT383 for young children, ages 2 to 5, with a rare disease called nephropathic cystinosis. This condition affects the kidneys, causing them to not work well. DFT383 is a special type of treatment called cellular gene therapy, which aims to fix the problem at its source. Participants will either receive DFT383 or the usual care (Standard of Care, SoC).

Cohorts: The study has two groups: Cohort 1 will receive DFT383, while Cohort 0 will receive the standard treatment. About 15 children will be in each group. Cohort 1 will last up to 32 months, and Cohort 0 will last up to 24 months.

Eligibility: Children must be aged 2 to 5, be on cysteamine medicine for at least 6 months, and have a history of nephropathic cystinosis. They cannot participate if they've had a kidney transplant or certain other medical issues.

• Study Length: Up to 32 months for Cohort 1, up to 24 months for Cohort 0.
• Visits Needed: Regular check-ups will be required.
• Risks: Potential risks are involved, and more details will be provided to guardians.