I am heterozygous 677T. 1298C is fine. I was also suspicious of MTHFR in the beginning. MTHFR seems all the craze. My functional B12 levels have always been okay. My Folate levels have been borderline low despite large dosing. My Glutathione levels were low per SpectraCell and MPP. I tried lifting my Glutathione levels via various Methylation protocols and had no luck. Instead I switched gears to improving glutathione recycling by supporting Glutathione Reductase via B1, B2, and B3. It appears that high dose B1 TTFD may have been 1 of the missing components in my health. We have one data point that supports the use of TTFD for me which resulted in increased Glutathione. We'll do another nutrient test in Feb 2018. I am now switching to why is this happening. What might be causing this excessive oxidative stress and need for increased recycling capacity?