Individuals with JAK1 c.1648+1272GG plus JAK1 c.991-27CC plus STAT3 c.*1671TT and JAK1 c.1648+1272GG plus JAK1 c.991-27CC plus STAT3 c.-1937CC genotypes were under 2.66- and 2.35-fold increased risks of CM development than others, respectively, when combinations of three SNVs were considered. The gene discussed is JAK1; the disease is cutaneous mastocytosis.