DHFR and malaria: In addition, both mutations in the dhps (S436A, A437G, K540E, A581G, and A613S) and dhfr (N51I, C59R, S108N, and I164L) genes have been shown to confer resistance to SP, used alone for intermittent preventive treatment in pregnant women (IPTp) and in combination with amodiaquine for seasonal malaria chemoprevention (SMC) [25, 27].