We found that SMARCAL1 regulates differentiation of K562 cells in response to phorbol myristate acetate (PMA) by transcriptionally repressing c-myc expre transcriptionally repressing c-myc expression leading us to leading us to propose that the phenotypic manifestation of SIOD could be due to the changes in gene expression profiles of key transcription factors which are directly or indirectly regulated by SMARCAL1 with the negative regulation of c-myc presented in this paper being one such example. This evidence concerns the gene MYC and Schimke immuno-osseous dysplasia.