Every single disease _will_ have a genetic “cause”.
Every… single… one… because we are all built on genes.
Any chemicals that affects us must work on us through our gene products. Chemicals can only work on us through the enzymes, proteins, and regulatory systems that make us up.
So there is some hypothetical enzyme that adds atoms to a colorless molecule ClearMol. (CM) to create a blue color BlueMol. (BM) and that blue color gives us blue eyes.
Hypothetical: There is a pesticide(P) that is acted upon by this same enzyme. Termed “false substrate” (Every single enzyme cross reacts with other chemicals. This is why there are enzyme inhibitors and medical side effects to drugs.)
Back to our hypothetical — When our human [blue-eye]enzyme acts on the pesticide it does the same thing it would normally do and adds the same group of atoms — but to the pesticide (Pesticide*). Now the changed pesticide Pesticide* has different biological properties. Different properties than the original pesticide that the companies tested. Now this modified pesticide (Pesticide*) causes disease. This is all hypothetical but …. After years of scientific investigation the enzyme for blue eyes would be identified as a cause of the disease for the reason stated at the start that it is modifying the pesticide. Some people with blue eyes get this disease and no one else does.
Also you could chemically (medically) block the function of the blue-eyed enzyme and prevent the disease.
Ergo The genetic cure for this “disease” then would be to “cure” us of the gene for blue eyes. Or chemically cure us by inhibiting the function of the enzyme. Wow a new drug you could sell :-). This, in my opinion, is the danger of designer babies and really most drugs.
In my opinion it would be the pesticide that we should cure ourselves of.
Learn about your world.