There were no significant differences between Osx-Mdm2fl/+ (Mdm2 haploinsufficient MSCs) and Vav-Cre;Mdm2fl/+ (Mdm2 haploinsufficient hematopoietic stem cells) groups in their response to IR, as both showed severe thrombocytopenia. The gene discussed is SP7; the disease is Thrombocytopenia.