All-trans retinoic acid (ATRA) is used in the treatment of acute promyelocytic leukemia (APL) [1, 2], which is characterized by a chromosomal translocation involving the retinoid-receptor, RARα, resulting in the production of the PML-RARα oncogene [2–4]. The gene discussed is RARA; the disease is acute promyelocytic leukemia.