First a definition, we'll be using the wikipedia version of the philosophical movement of transhumanism. This is the idea that humans will reach technologies that allow them to alter the human frame. There's two major ideas in that people will augment the body through cybernetic prosthetics (cyborgs) or (as we'll be discussing mostly) that people will edit the human genome and create biologically enhanced humans.
Second, a very popular news article (which I believe is our first steps toward a transhumanist future). Recently, a chinese doctor reportedly had edited the genome of a pair of twins so that they were resistant to HIV. Showing that we are very near the technologies described by transhumanists and the problems those technologies create. This stirred up a veritable firestorm of backlash from scientists the world over and the Chinese government which has sanctioned the researcher since. And this is the foundation of the question.
In a not so distant future, the technology to clean the human genome of disease exists. It spawns the logical leap that you can improve the human frame (in any number of ways from intelligence, charisma, strength, etc.) But as humans are ought to do there is resistance against this idea. Anyone who is a known subject of these treatments is discriminated against. Violence is uncommon but not unheard of against people like this. And a common legal argument exists that since these beings aren't technically human (having been altered to a state of extra-human status) that human protections shouldn't be granted to them (although they have to follow all human laws).
So what laws would need to exist (and be enforced broadly) or need to be created to support altered humans in the United States?
There is an additional criteria in this question. A lot of the backlash was based on ethical concerns and not legal matters in our real world example. So (if possible) how could ethics issues be resolved with these laws?
Just some ethics issues to consider.
Right to consent: Does a fetus have rights to not consent to alterations to its genome? Does the parent's rights as medical proxy supersede that? Seeing as this technology is currently being used in this way, this seems likely to appear as an issue.
Human alteration: Is it proper to alter the human body at all? You'll find a fair few that believe it's entirely unethical to alter the human structure.
Eugenics: Transhumanism can be easily associated with the negative sides of eugenics. After all, cleaning the human genome can turn into getting rid of the unwanted traits of society even if they aren't flaws.