This is a single-center, randomized, placebo-controlled, crossover outpatient study with 15 subjects receiving one infusion of autologous umbilical cord blood (AUCB) containing a minimum of 10 million total nucleated cells per kilogram (TNC/kg) and 15 subjects receiving an infusion of placebo (saline). After the 24-week follow-up testing is conducted, the groups will crossover so that patients who initially received AUCB will receive placebo and patients who received placebo at baseline will receive the cord blood. Both groups will be tested again 24-weeks after infusion. The neuropsychologist, PI, staff from Cord Blood Registry (CBR), and parents will be blinded as to the infusion sequence.

The duration of participation for each study subject is approximately 55 weeks. This includes one screening visit over a period of approximately 6 weeks, one visit for baseline testing, one day for infusion of TNC (minimum 10 million/kg) or saline placebo followed by 24 weeks of follow-up. A second baseline visit is conducted at week-24 with the second infusion of TNC or saline placebo occurring 5-7 days after. Twenty-four additional weeks of follow-up occur after the second infusion.