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Influence of MTHFR genotype on whole blood folate measured by LC/MS/MS, microbiologic and BioRad assay
Author(s) -
Fazili Zia,
Pfeiffer Christine M.,
Zhang Mindy,
Gallagher Margaret,
Nikolova Stanimila,
Koontz Deborah
Publication year - 2007
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.21.5.a348-c
Subject(s) - methylenetetrahydrofolate reductase , genotype , folic acid , chemistry , medicine , biochemistry , gene
Red blood cells of individuals who carry two copies of the 5‐methylenetetrahydrofolate reductase polymorphism (MTHFR C677T) contain other reduced folate forms in addition to 5‐methyl‐tetrahydrofolic acid (5CH 3 THF). We analyzed 112 WB lysates (C/C n = 51, C/T n = 44, T/T n = 13) for folate species by LC/MS/MS and for total folate (TFOL) by microbiologic (MA) and BioRad (BR) assay. Subjects with C/C and C/T genotype displayed the same pattern of folate species distribution (mean [SD]): 5CH 3 THF (83% [3%]), 5‐formyltetrahydrofolic acid (5CHOTHF, 14% [2%]), 5,10‐methenyltetrahydrofolic acid (5,10CH=THF, 2% [2%]), and tetrahydrofolic acid (THF, 1% [1%]). Subjects with T/T genotype showed a different pattern: 5CH 3 THF 62% [20%], 5,10CH=THF 19% [15%], 5CHOTHF 15% [2%], and THF 5% [4%]. The sum of folate species (mean [SD], nmol/L) by LC/MS/MS (406 [127]) correlated well with TFOL (nmol/L) measured by MA (444 [144], R 2 = 0.89) and by BR (248 [74], R 2 = 0.80). TFOL by LC/MS/MS was slightly lower than TFOL by MA: 6%, 11%, and 17% for subjects with C/C, C/T, and T/T genotype. TFOL by BR was much lower than TFOL by LC/MS/MS: 41%, 40%, and 27% for subjects with C/C, C/T, and T/T genotype. This is in agreement with spiking recovery findings in WB lysate for the BR: 5CH 3 THF 51%, 5CHOTHF 17%, THF 152%, and 5,10CH=THF 115%. Contrary to previous reports, we cannot confirm lower TFOL concentrations in subjects with T/T genotype.