[motive]

Can you elaborate on the MTHFR mutation? I did supplementation in the past with similar results to the above commenter.

[zamalek]

It's a pretty common mutation that severely inhibits (depending on how many of the genes are mutated) methylation of folate in the liver. This is an important source of methyl groups for chemical processes, such as those that include NAD.

There's plenty more on Google, including the interaction between an MTHFR mutation and NAD supplementation.