title: Single nucleotide polymorphisms in homocysteine metabolism pathway genes: association of CHDH A119C and MTHFR C677T with hyperhomocysteinemia.
abstract: BACKGROUND
  An elevated level of homocysteine (hyperhomocysteinemia) has been implicated as an independent risk factor for cardiovascular diseases. Deficiency of dietary factors like vitamin B(12), folate, and genetic variations can cause hyperhomocysteinemia. The prevalence of hyperhomocysteinemia in the Indian population is likely to be high because most Indians adhere to a vegetarian diet, deficient in vitamin B(12). In the
  
  
  BACKGROUND
  deficiency, variations in genes involved in homocysteine metabolism might have a greater impact on homocysteine levels.
  
  
  RESULTS
  We genotyped 44 nonsynonymous single-nucleotide polymorphisms (nsSNPs) from 11 genes involved in homocysteine metabolism and found only 14 to be polymorphic. These 14 nsSNPs were genotyped in 546 individuals recruited from a tertiary care center in New Delhi, India, and it was found that choline dehydrogenase (CHDH A119C) and methylenetetrahydrofolate reductase (MTHFR C677T) were significantly associated with plasma total homocysteine levels (P=0.009 and P=0.001, respectively). These 2 SNPs were further genotyped in 330 individuals recruited from the same center, and the association remained significant even after increasing the sample size. Furthermore, we found the possibility of a significant interaction between vegetarian diet and the 2 polymorphisms that could explain the variation of homocysteine levels. We also genotyped all the polymorphic nsSNPs in apparently healthy individuals recruited from 24 different subpopulations (based on their linguistic lineage) spread across the country to determine their basal frequencies. The frequencies of these SNPs varied significantly between linguistic groups.
  
  
  CONCLUSIONS
  Vegetarian diet along with CHDH A119C and MTHFR C677T play an important role in modulating the homocysteine levels in Indian population.
authors.affiliation: Institute of Genomics and Integrative Biology, Delhi, India.
authors.forename: Jitender
authors.initials: J
authors.lastname: Kumar
authors.forename: Gaurav
authors.initials: G
authors.lastname: Garg
authors.forename: Arun
authors.initials: A
authors.lastname: Kumar
authors.forename: Elayanambi
authors.initials: E
authors.lastname: Sundaramoorthy
authors.forename: Krishna Rao
authors.initials: KR
authors.lastname: Sanapala
authors.forename: Saurabh
authors.initials: S
authors.lastname: Ghosh
authors.forename: Ganesan
authors.initials: G
authors.lastname: Karthikeyan
authors.forename: Lakshmy
authors.initials: L
authors.lastname: Ramakrishnan
authors.forename: Shantanu
authors.initials: S
authors.lastname: Sengupta
mesh_terms: D000328:Adult; D053898:Biosynthetic Pathways; D050545:Choline Dehydrogenase / Q000235:genetics* / Q000378:metabolism; D006710:Homocysteine / Q000378:metabolism*; D006801:Humans; D020138:Hyperhomocysteinemia / Q000201:enzymology* / Q000235:genetics* / Q000378:metabolism; D007194:India; D008297:Male; D042965:Methylenetetrahydrofolate Reductase (NADPH2) / Q000235:genetics* / Q000378:metabolism; D008875:Middle Aged; D017354:Point Mutation; D020641:Polymorphism, Single Nucleotide
chemical_list: D006710:Homocysteine; D050545:Choline Dehydrogenase; D042965:Methylenetetrahydrofolate Reductase (NADPH2)