Acute myeloid leukemia (AML) in children with cytogenetic aberrations like translocation t(7;12)(q36;p13) is associated with inferior outcome. The translocation can lead to a fusion transcript MNX1::ETV6 but also to activation of MNX1 transcription. We generated an AML mouse model by transplantation of fetal liver cells with ectopic expression of MNX1. AML was highly penetrant in immunocompromised and less penetrant in immunocompetent mice. Transforming capacity was restricted to fetal liver cells and could not achieved with adult bone marrow cells, in concordance with the clinical finding that t(7;12)(q36;p13) is mostly restricted to infants. Ectopic expression of MNX1 led to increased H3K4methylation and reduced H3K27me3, possibly through its interaction with methyl transferases. MNX1 expression was accompanied with changes in genome wide chromatin accessibility , increased DNA damage, depletion in the LSK population and skewing toward the myeloid lineage. These effects, together with leukemia development, could be prevented by the S-adenosylmethionine analogue Sinefungin that acts as a SAM competitor and a pan methyltranferases inhibitor. Expression profiles of a human iPSC AML model with t(7;12) and of TARGET pediatric AML and TCGA patients support the rationale for targeting MNX1 and downstream pathways.