ATM and Immunodeficiency: Because there are no cures for A-T, we aimed to tackle immunodeficiency and prevent cancer onset/progression by transplantation therapy.<h4>Methods</h4>Enriched hematopoietic stem/progenitor cells (HSPCs), collected from bone marrow of wild-type mice, were transplanted in the caudal vein of 1 month old conditioned Atm<sup>-/-</sup> mice.<h4>Results</h4>Genomic analyses showed that transplanted Atm positive cells were found in lymphoid organs.