Mutations involving the activating domain of KIT, mostly the D816V KIT mutation, are found in >90% of patients with SM when highly-sensitive diagnostic techniques are used (Garcia-Montero et al., 2006; Kristensen et al., 2014; Jara-Acevedo et al., 2015).This mutation leads to a constitutive SCF-independent activation of the receptor (Orfao et al., 2007; Arock et al., 2015) favoring downstream signaling intracellular pathways that promote MC proliferation, growth, survival and activation (Cruse et al., 2014). The gene discussed is KIT; the disease is systemic mastocytosis.