MTHFR A1298C causes an increase in ammonia because the mutation decreases the body's ability to generate & recycle BH4. BH4 is used to detox ammonia.
Lyme generates ammonia as a toxin, thus increasing the burden on BH4. Aluminum toxicity also decreases the body's ability to eliminate ammonia, further burdening BH4.
To address this, one may need to reduce their intake of foods that increase ammonia in the body (high protein foods), and use Yucca Root powder sprinkled on meals containing protein-rich foods.
Also, there is a Charcoal/Magnesium Flush at the below website link that can help remove excess ammonia from the gut.
Scroll down to "Understanding MTHFR A1298C +" on this webpage for more info:
www.dramyyasko.com/resources/autism-pathways-to-recovery/chapter-6/