My firstborn son has a genetic disorder and a long list of issues. I figured I had until he was about five or so to do anything meaningful about it. This turned out to not be true. The window for intervention was much longer.
He's 32 and much more functional than I ever expected him to be, though he still lives with me for now.
He still has zero interest in a romantic relationship. He and I have the same genetic disorder. I do not share his general lack of interest in romantic relationships.
I will suggest you try to not automatically lump in all of your child's characteristics with this one detail that he has a mutation. You might read up a bit on "ace" or "aromantic" people. There are people who just aren't terribly interested in romance. It's really not some bizarre defect.
I did see your other comment. I did understand that this was new and apparently unique.
I think about this a lot and don't have good answers. All I can say is that I have 3 goals for my daughter - and she doesn't need to be a 100% normal child to achieve any of those goals. 1) I hope my child is not in pain 2) I hope my child feels loved 3) I hope my child can find beauty in the world.
So, your example of the happiness / awareness tradeoff really applies to everyone. It probably applies to ancient myths like Adam+Eve, Prometheus etc. too. From history it is clear that seeking awareness at the risk of existential discomfort is something that people do.
Having said all that, this is an incredibly tough decision to make and is solely up to your family.
just fyi this is actually an active research topic, c.f. https://en.wikipedia.org/wiki/Oogonial_stem_cells#Research
The poor motor function is probably related to poor myelination of the nerves in his body, as his proprioception and pain perception are affected.
The problem with some mutations like this, is that they have an effect on the development of the brain from the start of the development and that fixing the gene (or better its RNA transscription) will not undo that development. The results of IQ tests seems to indicate that with my sons mutation, there is a problem with the myelination in his brain. Myeliniation is a process that starts before birth and continues into adolescent. At the moment he is quite happy and functioning well within his limits. His 'academic' IQ is rather low, but in some areas, he surpases the average person by far. He has a great sense of humor and people like him. In his case, I am really afraid what would happen if we would administer him a drug that would compensate for the genetic defect. Would he go through another fase of brain development and having to cope with all kinds of changes. Could he end up being less happy, because it would remove his ignorance about certain things. For example, at the moment he has no desire for a romantic relationship, but getting such a desire and than still not being able to satisfy it, could make him very unhappy.