CD34 and myelodysplastic syndrome: At the time of writing this review, the phase 1/2 (HGB-206) and phase 3 (HGB-210, NCT04293185) studies of lentiviral vector BB305 gene therapy for SCD, as well as the marketing of Zynteglo, are temporary suspended due to a reported Suspected Unexpected Serious Adverse Reaction of acute myeloid leukemia (AML).63 A case of MDS in a SCD patient treated in the HGB-206 trial, who did not have MDS before myeloablation, was also observed.64 The absence of vector integration in CD34+ blasts excludes lentiviral vector-mediated oncogenesis.