title: MAT1A variants modulate the effect of dietary fatty acids on plasma homocysteine concentrations.
abstract: OBJECTIVE
  Dietary n-3 polyunsaturated fatty acids (PUFAs) are associated with decreased plasma homocysteine (Hcy), an important biomarker for cardiovascular disease. The S-adenosylmethionine synthetase type-1 (MAT1A), an essential enzyme in the conversion of methionine to S-adenosylmethionine, plays a key role in homocysteine metabolism. This study investigated the interaction between dietary fatty acids and MAT1A genotypes on plasma Hcy concentrations among Boston Puerto Ricans.
  
  
  RESULTS
  Plasma Hcy and MAT1A genotypes were determined in 994 subjects of the Boston Puerto Rican Health Study. Dietary fatty acid intakes were assessed by interviews using a questionnaire adapted from the NCI/Block food frequency form.
  
  
  RESULTS
  In the cross-sectional analysis, genetic variant MAT1A 3U1510 displayed a significant interaction with dietary n-3:n-6 PUFA ratio in determining plasma Hcy (p-value for interaction = 0.025). 3U1510G homozygotes had significantly lower plasma Hcy concentration than major allele homozygotes and heterozygotes (AA + AG) (p-value for trend = 0.019) when the n-3:n-6 ratio was >0.09. Two other MAT1A variants, d18777 and i15752, also showed significant interactions with different constituents of dietary fat influencing Hcy concentrations. Furthermore, haplotypes consisting of three variants displayed a strong interaction with n3:n6 ratio influencing Hcy concentrations.
  
  
  CONCLUSIONS
  Our results suggest that MAT1A genotypes appear to modulate effects of dietary fat on plasma Hcy.
authors.affiliation: Department of Food Science and Nutrition, Zhejiang University, Hangzhou 310029, China.
authors.forename: T
authors.initials: T
authors.lastname: Huang
authors.forename: K
authors.initials: K
authors.lastname: Tucker
authors.forename: Y
authors.initials: Y
authors.lastname: Lee
authors.forename: J
authors.initials: J
authors.lastname: Crott
authors.forename: L
authors.initials: L
authors.lastname: Parnell
authors.forename: J
authors.initials: J
authors.lastname: Shen
authors.forename: C
authors.initials: C
authors.lastname: Smith
authors.forename: J
authors.initials: J
authors.lastname: Ordovas
authors.forename: D
authors.initials: D
authors.lastname: Li
authors.forename: C
authors.initials: C
authors.lastname: Lai
mesh_terms: D000368:Aged; D003430:Cross-Sectional Studies; D015525:Fatty Acids, Omega-3 / Q000008:administration & dosage*; D043371:Fatty Acids, Omega-6 / Q000008:administration & dosage*; D005260:Female; D006710:Homocysteine / Q000097:blood*; D006801:Humans; D008297:Male; D008716:Methionine Adenosyltransferase / Q000235:genetics*; D008875:Middle Aged; D020641:Polymorphism, Single Nucleotide
chemical_list: D015525:Fatty Acids, Omega-3; D043371:Fatty Acids, Omega-6; D006710:Homocysteine; C506577:MAT1A protein, human; D008716:Methionine Adenosyltransferase