DHFR and Plasmodium falciparum malaria: The presence of five mutant alleles, the dhfr/dhps “quintuple mutant”, including the dhfr substitutions N51I, C59R, and S108N and the dhps substitutions A437G and K540E, are associated with a very high rate of failure when SP is used for the treatment of uncomplicated falciparum malaria [4].