MTHFR and Dravet syndrome: Therefore, we selected the SNPs considering their influence on methylation during development and later in life, and we conducted a study to investigate the association between the MTHFR rs1801133, MTHFR rs1801131, MTRR rs1801394, DNMT1 rs2228611, DNMT3A rs1550117, DNMT3B rs1569686, and DNMT3B rs2424913 gene polymorphisms and CHDs in DS individuals and controls.