['sickle cell disease']
['hydroxyurea']

        Inclusion Criteria

          1. Pediatric patients with documented sickle cell anemia (typically HbSS supported by
             hemoglobin electrophoresis, complete blood count, and peripheral blood smear)

          2. Age range of 1.00-9.99 years, inclusive, at the time of enrollment

          3. Weight at least 10.0 kg at the time of enrollment

          4. Parent or guardian willing and able to provide written informed consent, with child's
             verbal assent as per local IRB/Ethics Board requirements

          5. Willingness to comply with all study-related treatments, evaluations, and follow-up

        Exclusion Criteria

          1. Known medical condition making participation ill-advised, (e.g., acute or chronic
             infectious disease, HIV, or malignancy)

          2. Acute or chronic severe malnutrition determined by impaired growth parameters as
             defined by WHO (weight for length/height or weight-for-length/height >3 z-scores below
             the median WHO growth standards, as defined in Appendix I)

          3. Pre-existing severe hematological toxicity (temporary exclusions)

               1. Anemia: Hb <4.0 gm/dL

               2. Anemia: Hb <6.0 gm/dL with ARC <100 x 109/L

               3. Reticulocytopenia: ARC <80 x 109/L with Hb <7.0 gm/dL

               4. Thrombocytopenia: Platelets <80 x 109/L

               5. Neutropenia: ANC <1.0 x 109/L

          4. Blood transfusion within 60 days before enrollment (temporary exclusion)

          5. Hydroxyurea use within 6 months before enrollment
      