Thanks, Lindy. Yes, it is true that taking folate will mask results, but what I need to know is how long it takes to clear the system. One thing I saw somewhere seemed to indicate it can be a very long time (weeks or months?). It's all so new & complex, like everything I try to figure out. There is some evidence in the literature for a linkage to PD, so it would be good, esp. for those of us who do have the mutation, to figure it out if possible.