MTHFR A1298C heterozygous effect on converting BH2 to BH4

I have recently found out I have MTHFR A1298C heterozygous polymorphism. I have been told that this effects the amount of BH4 I produce (or at least the rate it is recycled from BH2). I am yet to find references that fully explain this process and evidence to back up that MTHFR A1298C hetero does actually slow/inhibit the conversion of BH2 to BH4 (or that MTHFR is actually involved in this conversion at all). Also several references I have found deny that this occurs. I’ll like to just be able to take my doctors (and many people on the internets) word for it, but thats not in my nature, I need to see the evidence myself. Since the implications of reduced BH4 are obviously potentially immense (for me and at least one of my parents and my two children) I feel I need to clarify this before I can really accept that I have an issue. I am yet to fully go though Amy Yaskos info, so I might find my answers there, but I have already read so much it is doing my head in and thought you could point me straight to the answer I’m looking for. Any clarification of this process would be appreciated.