The only scary thing I read about MTRR A66G is the brain tumor thing.
I thought, "Brain tumor thing, what brain tumor thing?" and so I looked at this--
"The highest risk of meningioma was associated with heterozygosity for both
MTHFR variants [odds ratio (OR), 2.11; 95% confidence interval (95% CI), 1.42-3.12]. The corresponding OR for glioma was 1.23 (95% CI, 0.91-1.66).
A significant association between risk of meningioma and homozygosity for
MTRR 66G was also observed (OR, 1.41; 95% CI, 1.02-1.94).
"Similarly, the AG genotype [of MTRR A66G] was also associated with an increased risk albeit nonsignificantly (OR, 1.21; 95% CI, 0.94-1.55"
"Our findings provide support for the role of folate metabolism in the development of primary brain tumors."
http://cebp.aacrjournals.org/content/17/5/1195.full
Looks like I have an odds ratio of 2.11 for a meningioma from double-hetero C677T/A1298C, plus a 1.23 odds ratio for a glioma from the same, and a bonus 1.21 odds ratio for a meningioma from my hetero MTRR A66G.
I think 23andMe should really have reports available for these genes.