This study is for kids under 13 years old with sickle cell disease (SCD), a condition where blood cells are shaped like a sickle and can block blood flow. They need a sibling under 13 who can donate bone marrow. Before the procedure, doctors will check if the child is healthy enough for the transplant, which takes 2-3 months. The child will be given special medicine called conditioning to prepare for the transplant. After getting the bone marrow, they'll stay in the hospital for 4-6 weeks. After leaving the hospital, they will need regular clinic visits for 6-12 months and yearly check-ups later.

• This study lasts about 2 years, including hospital and clinic visits.
• The transplant might help kids with SCD feel better long-term, but there are risks involved.
• Participants need a sibling donor who doesn’t have SCD.