Studies have shown the involvement of MTHFR or DNMT3B polymorphisms in inflammatory diseases.20 , 21 Recently, our group revealed the association of the 149C→T DNMT3B (rs2424913) polymorphism with periodontitis,22 but not for C677T MTHFR (rs1801133). The gene discussed is MTHFR; the disease is periodontitis.