Future sci-fi upper class no illnesses DNA

[Danny]

Hi this is my first post and I only remember tiny parts of the book so sorry if I can't describe it that well. The book is about an upper class that has their DNA/genetics changed so they appear perfect and don't get illnesses. Near the end of the book the sister (I think) of the protagonist becomes ill and he takes her to them to see if they can help. They inject her with their DNA and she gets better. Sorry if too vague

[Justanotherbiblophile]

The only problem with being vague is that you're going to get a reading list, instead of an answer. :)

Here's my suggestion, based on a cursory glance (instead of having read the book, it's in the tbr pile).

Beggars in Spain

[Cupcakedoll]

[Andy]

I saw this old thread https://www.goodreads.com/topic/show/... that might be looking for the same book.

[Lobstergirl, au gratin]

Danny, are you still looking for this or did you find it?