Nevertheless, the frequency of the <i>G</i> allele of rs1801133 of <i>MTHFR</i> was higher in the RDD group and the frequency of the <i>C</i> allele of rs6264 of <i>BDNF</i> was higher in the MDD group.
Low folate intake in the presence of the functional MTHFR 677 C > T (rs1801133) polymorphism is an important cause of elevated homocysteine levels previously implicated in major depressive disorder (MDD) and many other chronic diseases.