Effect of genetic polymorphisms involved in folate metabolism on the concentration of serum folate and plasma total homocysteine (p-tHcy) in healthy subjects after short-term folic acid supplementation: a randomized, double blind, crossover study

Table 4 Concentration of serum folate associated with combined polymorphisms before and after supplementation with folic acid

			Baseline serum folate	p value for the comparison between polymorphism combinations	After 2 weeks serum folate	p value for the comparison between polymorphism combinations
	MTHFR-677C>T
MTHFR-1298A>C
AA	CC	(12)	19.6 ± 7.5		36.3 ± 8.8*¹
AC+CC	CC	(28)	17.3 ± 5.6		55.6 ± 47.2	AC+CC,CC–AC+CC,CT+TT (p = 0.005)
AA	CT+TT	(34)	17.2 ± 6.1		35.2 ± 21.9
AC+CC	CT+TT	(17)	15.5 ± 6.8		29.6 ± 11.1
MTHFD1-1958G>A
GG	CC	(13)	17.7 ± 6.5		50.1 ± 44.3*²
GA+AA	CC	(27)	18.1 ± 6.2		49.3 ± 39.0	GA+AA,CC–GG,CT+TT (p = 0.003)
GG	CT+TT	(20)	16.5 ± 5.8		29.1 ± 10.0
GA+AA	CT+TT	(31)	16.7 ± 6.7		35.9 ± 22.6
MTR-2756A>G
AA	CC	(24)	16.6 ± 6.2		54.3 ± 45.9*³
AG+GG	CC	(16)	20.1 ± 5.9		42.2 ± 29.1
AA	CT+TT	(30)	17.8 ± 6.9		35.1 ± 22.3
AG+GG	CT+TT	(21)	15.0 ± 5.0		30.3 ± 11.7
DHFR 19del
WW	CC	(18)	16.3 ± 5.4		50.8 ± 43.5
WD+DD	CC	(22)	19.3 ± 6.6		48.4 ± 37.9
WW	CT+TT	(16)	16.2 ± 5.1		33.4 ± 22.5
WD+DD	CT+TT	(35)	16.8 ± 6.8		33.2 ± 17.3
TS
3R3R	CC	(12)	16.4 ± 5.3		47.7 ± 41.0*⁴
2R2R + 2R3R	CC	(28)	18.7 ± 6.6		50.4 ± 40.5	2R2R+2R3R,CC−2R2R−2R3R, CT+TT (p = 0.008)
3R3R	CT+TT	(11)	15.3 ± 5.4		37.7 ± 27.6
2R2R + 2R3R	CT+TT	(40)	17.0 ± 6.5		31.9 ± 15.7
RFC1-80G>A
GG	CC	(14)	17.6 ± 6.1^#1		34.8 ± 11.3*⁵
GA	CC	(15)	19.2 ± 6.9		63.3 ± 44.8	GA, CC−GG,CT+TT (p < 0.0001)
AA	CC	(11)	16.8 ± 5.6		48.0 ± 52.0
GG	CT+TT	(12)	15.4 ± 3.5		26.1 ± 10.0	GA,CC−GA,CT+TT (p = 0.0002)
GA	CT+TT	(26)	14.7 ± 4.7	GA,CT+TT−AA,CT+TT (p = 0.002)^#2	30.4 ± 17.9
AA	CT+TT	(13)	21.7 ± 8.4		46.9 ± 22.0

Data are presented as mean ± SD. Number of subjects in parentheses. Serum folate concentration is given in nmol/L. ANOVA test
^#1 p = 0.03, ^#2 p = 0.002, *¹ p = 0.02, *² p = 0.03, *³ p = 0.03, *⁴ p = 0.04, *⁵ p = 0.0003

ISSN: 1865-3499