title: Maternal one-carbon metabolism, MTHFR and TCN2 genotypes and neural tube defects in India.
abstract: BACKGROUND
  Neural tube defects (NTDs) are among the most common severe congenital malformations, representing a long-term public health burden in India. A deranged one-carbon metabolism and genes regulating this metabolism have been linked to NTDs. Vitamin B(12) deficiency is reported to be more prevalent than folate deficiency in the Indian population. We investigated the role of maternal nutritional and genetic markers related to one-carbon metabolism in the etiology of NTDs.
  
  
  METHODS
  We conducted a multicenter case-control study to compare plasma folate, vitamin B(12) , homocysteine and holo-transcobalamin levels, and polymorphisms in methylenetetrahydrofolate reductase (MTHFR, 677C>T, 1298A>C, 1781G>A and 236+724A>G) and transcobalamin (TCN2, 776C>G) genes, in 318 women with NTD-affected offspring (cases) and 702 women with apparently healthy offspring (controls). The samples were collected at diagnosis in cases and at delivery in controls.
  
  
  RESULTS
  We observed a significant association of high maternal plasma homocysteine concentrations with NTDs in the offspring (p = 0.026). There was no association of maternal folate or B(12) levels with NTDs (p > 0.05) but low maternal holo-transcobalamin predicted strong risk of NTDs in the offspring (p = 0.003). The commonly associated maternal polymorphism 677C>T in the MTHFR gene did not predict risk of NTDs in the offspring (p > 0.05) and 1298A>C and 1781G>A polymorphisms in MTHFR were protective (p = 0.024 and 0.0004 respectively). Maternal 776C>G polymorphism in TCN2 was strongly predictive of NTD in the offspring (p = 0.006).
  
  
  CONCLUSIONS
  Our study has demonstrated a possible role for maternal B(12) deficiency in the etiology of NTDs in India over and above the well-established role of folate deficiency.
authors.affiliation: Diabetes Unit, KEM Hospital Research Center, Rasta Peth, Pune, India.
authors.forename: Koumudi
authors.initials: K
authors.lastname: Godbole
authors.forename: Panjalingam
authors.initials: P
authors.lastname: Gayathri
authors.forename: Smita
authors.initials: S
authors.lastname: Ghule
authors.forename: Batchu Venkatanaga
authors.initials: BV
authors.lastname: Sasirekha
authors.forename: Amruta
authors.initials: A
authors.lastname: Kanitkar-Damle
authors.forename: Nilam
authors.initials: N
authors.lastname: Memane
authors.forename: Seshadri
authors.initials: S
authors.lastname: Suresh
authors.forename: Jayesh
authors.initials: J
authors.lastname: Sheth
authors.forename: Giriraj Ratan
authors.initials: GR
authors.lastname: Chandak
authors.forename: Chittaranjan S
authors.initials: CS
authors.lastname: Yajnik
mesh_terms: D000328:Adult; D016022:Case-Control Studies; D005260:Female; D005492:Folic Acid / Q000235:genetics / Q000378:metabolism; D020022:Genetic Predisposition to Disease; D006710:Homocysteine / Q000097:blood*; D006801:Humans; D007194:India / Q000453:epidemiology; D042965:Methylenetetrahydrofolate Reductase (NADPH2) / Q000235:genetics / Q000378:metabolism; D009436:Neural Tube Defects / Q000201:enzymology / Q000453:epidemiology / Q000235:genetics; D020641:Polymorphism, Single Nucleotide; D014155:Transcobalamins / Q000235:genetics / Q000378:metabolism; D014805:Vitamin B 12 / Q000235:genetics / Q000378:metabolism; D014806:Vitamin B 12 Deficiency / Q000201:enzymology / Q000453:epidemiology / Q000235:genetics
chemical_list: D014155:Transcobalamins; D006710:Homocysteine; D005492:Folic Acid; D042965:Methylenetetrahydrofolate Reductase (NADPH2); D014805:Vitamin B 12