I found it interesting that a number of the links in the 23andme statement are studies that actually show significant correlation between MTHFR mutations and cancer, heart disease, etc. I've also seen studies that indicate its not the mutation thats causing it - it is low folate or high homocysteine levels (but that is caused by the mutation).

I have the A1298C mutation, which isn't the worst. I also had a fairly acute onset of SFN symptoms - going on 3 years ago now. After going on a supplement routine to address the mutation, the SFN has not progressed, and has gotten somewhat better. I can't say for sure that the mutation caused the SFN, but I have felt better with the supplements, so will continue to take them. The cost of the supplements does add up over time, but I'm fortunate enough that it is not a huge financial burden to me.