In combinations of two SNVs, individuals with JAK1 c.1648+1272GG plus STAT3 c.*1671TT, JAK1 c.1648+1272GG plus STAT3 c.-1937CC, JAK1 c.991-27CC plus STAT3 c.*1671TT, JAK1 c.991-27CC plus STAT3 c.-1937CC, and STAT3 c.*1671TT plus STAT3 c.-1937CC genotypes had 2.54-, 2.15-, 2.32-, 2.10-, and 1.90-fold increased risks of developing CM than those with the remaining genotypes, respectively. This evidence concerns the gene JAK1 and cutaneous mastocytosis.