title: Increased resistance to malaria in mice with methylenetetrahydrofolate reductase (Mthfr) deficiency suggests a mechanism for selection of the MTHFR 677C>T (c.665C>T) variant.
abstract: The polymorphism 677C>T (NM_005957.4:c.665C>T/p.Ala222Val, rs1801133:C>T) in methylenetetrahydrofolate reductase (MTHFR) results in mild enzymatic deficiency and increased risk for several complex traits including adverse reproductive outcomes, birth defects, and heart disease. Despite these deleterious effects, homozygosity is high (5%-15%) in many populations, and among the highest in Mediterranean regions, where malaria was historically endemic and may have conferred a selective advantage for other mutations. We infected Mthfr-deficient (Mthfr(+) (/-) ) and MTHFR overexpressing (MTHFR(Tg) ) mice with Plasmodium berghei ANKA to induce cerebral malaria. Mthfr(+/-) mice survived longer (P < 0.02, log-rank test), and MTHFR(Tg) mice died earlier (P < 0.05, log-rank test) after infection compared with wild-type littermates. Flow cytometry revealed increased lymphocyte populations and increased CCR4(+) NK cells in spleen of Mthfr(+) (/-) mice; MTHFR(Tg) animals had decreased numbers of these NK cells. Interferon-γ and interleukin-10 immunoreactive proteins were increased and decreased, respectively, in brain of Mthfr(+/-) mice compared with wild-type. We suggest that mild MTHFR deficiency protects against malarial infection and that this phenomenon may have led to the high frequency of the 677C>T/c.665C>T variant in human populations.
authors.affiliation: Department of Human Genetics, McGill University, McGill University Health Center, Montreal, Quebec, Canada.
authors.forename: Danielle N
authors.initials: DN
authors.lastname: Meadows
authors.forename: Michal
authors.initials: M
authors.lastname: Pyzik
authors.forename: Qing
authors.initials: Q
authors.lastname: Wu
authors.forename: Sabrina
authors.initials: S
authors.lastname: Torre
authors.forename: Philippe
authors.initials: P
authors.lastname: Gros
authors.forename: Silvia M
authors.initials: SM
authors.lastname: Vidal
authors.forename: Rima
authors.initials: R
authors.lastname: Rozen
mesh_terms: D000818:Animals; D001921:Brain / Q000378:metabolism / Q000473:pathology; D005492:Folic Acid / Q000235:genetics; D006712:Homocystinuria / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D006801:Humans; D007371:Interferon-gamma / Q000096:biosynthesis; D016753:Interleukin-10 / Q000096:biosynthesis; D016779:Malaria, Cerebral / Q000209:etiology / Q000235:genetics* / Q000473:pathology; D042965:Methylenetetrahydrofolate Reductase (NADPH2) / Q000172:deficiency* / Q000235:genetics / Q000378:metabolism; D051379:Mice; D009128:Muscle Spasticity / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D010961:Plasmodium / Q000378:metabolism / Q000472:pathogenicity; D020641:Polymorphism, Single Nucleotide; D011618:Psychotic Disorders / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D012641:Selection, Genetic / Q000235:genetics*
chemical_list: D016753:Interleukin-10; D007371:Interferon-gamma; D005492:Folic Acid; C573423:MTHFR protein, human; D042965:Methylenetetrahydrofolate Reductase (NADPH2)
keywords: MTHFR; cerebral malaria; folate; genetic selection; infection