We had testing done on the genes that detoxify in the liver and Wally had problems with several of them. He doesn't clear anti-epileptic drugs and he was on anti-epileptic drugs for years. Also problems with aromatic hydrocarbons, valium and valium type meds--can't remember the others.
I feel that Wally's ALS was precipitated by a build up of toxicity due to mal-functioning genes.