I have just discovered that the rs662 SNP in my PON1 gene also has the TT alleles.
Just a few years prior to the beginning of my ME/CFS, I was chronically exposed for a year or so to a significant amount of organophosphate pesticides, due to a bad indoor pesticide contamination at home. The exposure was so severe that my testicles shut down semen production for around 6 months (organophosphates are known to reduce semen quality, but in my case, they caused a complete cessation of semen production). I also had severe mental symptoms during this period of exposure (confusion and psychosis). Other household members also suffered symptoms, but not nearly as bad as me. I expect that my TT allele was the reason I got hit so much worse than everyone else by this pesticide exposure.
Although I also caught a nasty virus just after this exposure, which I think played a major role in my development of ME/CFS, I do wonder just how much that horrible pesticide experience I went through also contributed to me getting ME/CFS.
One pesticide poisoning expert I spoke to told me that individuals who suffer significant organophosphate pesticide poisoning fall into two camps: those that slowly get better after a few years, and those that actually seem to further deteriorate over the subsequent years. So I wonder if my development of ME/CFS is in part due to this further deterioration over the years.
Farmers that use "sheep dip", which generally contains organophosphates, are 4 times more likely to develop ME/CFS, so there is definitely a link between organophosphate exposure and the development of ME/CFS. Ref:
1
Note that generally speaking, the pesticide residues in foods are negligible, and not a concern. Damaging pesticide exposure usually comes from accidental spillages, and garden, municipal and agricultural applications.
EDIT: actually it seems that for some organophosphate compounds, the TT allele may make PON1 slower at detoxifying them; and for other organophosphates, the TT allele may make PON1 faster at detoxification. See
this post.
So I don't think we can say that the TT allele on rs662 SNP uniformly slows the detoxification of organophosphates by PON1. If I understood correctly, I think you would need to look at this on a case-by-case basis, and see whether for the organophosphate in question, how the TT allele affects the detoxification rate of PON1.