TCN2 776C→G polymorphism tied to greater odds of peripheral neuropathy
Transcobalamin (TCN2) 776C→G polymorphism may increase the chances of peripheral neuropathy in the elderly, even with a normal vitamin B-12 status, a recent study suggests. This is particularly true if their folate intake is >2 times the recommended dietary allowance (RDA).
“The 776C→G polymorphism of the vitamin B-12 transport protein transcobalamin gene (rs1801198; Pro259Arg) is associated with a lower holotranscobalamin concentration in plasma,” according to researchers.
This outcome may lower the availability of vitamin B-12 to tissues even with adequate vitamin B-12 intake. Clinical outcomes linked to vitamin B-12 insufficiency could potentially be worsened by high folate intake, they added.
A cross-sectional study involving 171 participants was conducted to determine the association of the TCN2 776C→G polymorphism and folate intake with peripheral neuropathy in elders with normal plasma concentrations of vitamin B-12.
Participants came from a cohort of community-based, home-bound elderly individuals aged ≥60 years who underwent an evaluation by physicians, including an assessment for peripheral neuropathy. Researchers administered food-frequency to them, provided general health status questionnaires and collected a fasting blood sample from each person.
GG genotypes had threefold higher odds of neuropathy than CC genotypes (odds ratio [OR], 3.33; 95 percent CI, 1.15 to 9.64). GG genotypes had 6.9-fold higher odds of neuropathy than CC genotypes (OR, 6.9; 1.31 to 36.36) when folate intake was >2 times the RDA (800 μg).
No difference was found between the genotypes in the odds of peripheral neuropathy when folate intake was ≤800 μg (OR, 1.5; 0.18 to 12.33).