Consistent with the diagnosis of ETP-ALL, gain-of-function CSF3R and PTPN11 mutations and loss of function DNMT3A mutations have been described in ETP-ALL (Coustan-Smith et al. 2009; Zhang et al. 2012; Maxson et al. 2013), but not, to the best of our knowledge, in cortical or mature T-ALL. The gene discussed is DNMT3A; the disease is acute lymphoblastic leukemia.