A recent article on Science Daily caught my eye: Study links exposure to common pesticides to ADHD in boys. The article goes on to describe a study that links exposure to pyrethroid to ADHD, especially in boys.
Pyrethroid is a generic term for an organic compound that is commonly used in household pesticides. Permethrin is one type of pyrethroid, and it is used in agriculture as an insecticide, as a household pesticide, and also to prevent fleas and ticks. It works by slowing down the nervous system through activation of the sodium channel. The FDA claims it is safe for humans and most mammals, with the exception of cats.
A study published in 2011 in the Journal of Agriculture and Food Chemistry points to pathways of metabolism of permethrin. Phase I metabolism mainly uses CYP2E1, and Phase II metabolism is only through UGT1A9. [ref]
I have been working on a series of posts about the detoxification pathways and the genes involved. Putting together the pieces, I wonder if problems in the detox pathway contribute to the link to ADHD. Funny thing –when looking at the UGT enzymes and genetic polymorphisms, I had found out that cats lack this enzyme and that is why they can’t metabolize acetaminophen and, apparently, permethrin either. Makes sense now that you can use a dog flea collar on a cat.
Here are the posts related to CYP2E1 and UGT1A9. I did not find a lot of concrete information on what the polymorphisms in either gene do as far as the expression of the gene. Hopefully this can help you get started in researching if this is an area that impacts you or your family.