This is a hypothesis that may reconcile some anecdotes and has many hints suggested in the enzymological literature. First, make sure you get my MTHFR Protocol, my free 7-page quick guide to optimizing and personalizing your methylation status, here:  https://chrismasterjohnphd.com/blog/2019/03/01/start-here-for-mthfr-and-methylation For the written version with references, as well as the 58 comments, including from Susan Owens, head over to Substack: https://chrismasterjohnphd.substack.com/p/can-biotin-help-detoxify-oxalate