All of the GM products are made to be "nutritionally similar" to the same product family. While they are similar they do at times cause many problems in the system.
I remember about ten years ago that there was a small percentage of young girls in PR that had early breast development. If I remember correctly it was tied to some phthalic acid that the girls were thought to be receiving from cows milk who were eating GM crops. Plastics were thought to play some role.
I would be curious if a lab could analyze corn or wheat flour and tell if it came from genetically modified corn or wheat plants.
For corn, this can be done and it is done from time to time. Sometimes, product that’s purportedly non-GMO turns out to have trace amounts of GMO material, which is greatly distressing to the anti-GMO Luddites.
I presume that such testing can also be done for wheat, although there are not yet any real-world GMO samples to test.