RARG and mucopolysaccharidosis: The deletion of the retinoic acid receptor‐γ (RAR‐γ) in mice, using a homozygous mutant null mouse for the Rarg gene, led to the development of a myeloproliferative‐like syndrome (MPS‐like).(39) When BM from wild‐type mice was transplanted into Rarg−/− mice, the MPS‐like phenotype occurred, featuring overproduction of granulocytes and granulocyte/macrophage progenitors in the BM, spleen, and peripheral blood.