The primary objective of the study is to determine the safety and feasibility of intrathecal administration of DUOC-01 as an adjunctive therapy in patients with inborn errors of metabolism who have evidence of early demyelinating disease in the central nervous system (CNS) who are undergoing standard treatment with unrelated umbilical cord blood transplantation (UCBT). The secondary objective of the study is to describe the efficacy of UCBT with intrathecal administration of DUOC-01 in these patients.