The short answer is yes. The answer is yes because we currently do use specific gene markers to learn about important aspects of our health. There exist industries around risk assessments, pre-natal testing and counseling for potential parents just to name a few. Here’s a bit from a recent New York Times article titled Genes Now Tell Doctors Secrets They Can’t Utter,
Gloria M. Petersen, a genetic epidemiologist at the Mayo Clinic, and her colleagues ran into a disclosure problem in a study of genes that predispose people to pancreatic cancer. The 2,000 study patients had signed consents indicating whether they wanted to know about research findings that might be important to them. But the forms did not ask about sharing findings that might be important to their families, or about what the researchers should do if they discovered important information after the patients were dead.
Seventy-three of the study patients, almost all of whom are now dead, had one of three clinically important mutations. One predisposed them mostly to melanoma but also to pancreatic cancer. A second predisposed them primarily to breast and ovarian cancer. The third, a cystic fibrosis gene, can increase the risk of pancreatic cancer and can also be important in family planning. If a man and a woman each have this gene, they have a one-in-four chance of having a child with the disease.
Of course there are always complexities outside of the genome that complicate medical genetics, you’ve named only a few. There’s also a lot that’s lost in translation, pardon the pun, between the scientific literature and the press article. The ways in which university or institutions present their results can also lead to embellishments. Genes do not equal destiny and all that. As a general rule, anything that involves humans (let along genetics or gene therapy) is messy.
There are probably a lot of reasons why you haven’t encountered it and a lot of it probably has to do with your age. Medical genetics has made significant advancements since we, assuming we’re roughly the same age, were born. The most obvious indication of that is the ways in which sequencing is substantially faster, more automated and cheaper.
At some point you’ll encounter it, and if not, you probably died before they could roll out the technology that will be routine for future generations (as terrifying as that may sound.)