Figure 1.

Representative illustration of KIT gene (top) and protein (bottom) with mastocytosis-associated mutations. Listed are all reported KIT variants identified in mastocytosis (modified from [8]). Bolded mutations are known to constitutively activate KIT, qualifying as oncogenic variants and a minor criterion for SM. ^ Denotes KIT mutations found in germline configuration in familial cases, mainly in CM. Variants are arranged by affected exons of KIT cDNA, which align to KIT protein functional domains. Ig = Immunoglobulin, JM = juxtamembrane domain, TKD = tyrosine kinase domain, and TM = transmembrane domain.