I had a lot of improvement doing Dr. Amy Yasko's protocol using her genetic testing and stool tests and urine tests etc. and having her interpret them and guide me through the process of using the supplements to go around the "traffic jams" caused by my genetic SNPs. I was very severe (Canadian Consensus Criteria) for 5 years and it brought me from feeling like I wanted to die every day to actually feel like living was worthwhile. I could be up and around in the house (always having the couch nearby or recliner for very frequent rest) and then became able to go to church and to the grocery if I used my mobility scooter, and not have PEM as long as I didn't do it more than once a week. This took about 18 months, and it was expensive, but I believe it was very worth it for me. Although I haven't been able to get well enough to go back to work, my quality of life improved so very much. If I had the finances to be able to continue the full program I think I might have improved quite a bit more.
After I started feeling better I cut back on the program because of the expense. I just couldn't maintain it. But I recently found a link to the shortcut program that the late Rick K (I can't think of his last name now) and Dr. Amy came up with. This is cheaper and I had started to use it again, but my son got cancer and I was trying to help him with expenses so I let that go- not a good idea. When I am off it for a month or months it catches up to me and I relapse.
If someone I knew was interested in doing something with epigentics I would recommend testing done on Dr, Amy Yasko's site Holisticheal.com. If at all possible, I would recommend doing her full program- especially if you are severely ill because the results will probably be better, quicker, but if you can't afford it, you can't afford it.
With the shortcut program it is a lot easier and cheaper. I think the shortcut program is still be beneficial. You could do the genetic testing from Holisticheal.com and then use the results and follow the chart for the shortcut program.
Her books are extremely helpful in understanding the why behind epigenetics and her protocol.
Interesting to note that many people are aware of their MTHFR status which, if defective, requires more methyl donors and the need of methyl-tetra-hydra-folate as opposed to folic acid. But comparatively few are aware of their COMT status which, if defective, indicates that your body has a harder time dealing with methyl donors -so MTHFR status may indicate needing methyl-B12 but the COMT status may indicate that it's not a good idea to supplement with lots of methyl-B12, that hydroxy and/or adenosyl B12 might be safer. Apparently a sweet spot has to be found to supply enough methyl donors but not too many.
IMHO supplementing according to your genetics is a good base to start from and can help the other protocols that you add to work better.