It is increasingly realized that genetic polymorphisms affect our risks for certain diseases or predispose us to toxicity from certain drugs. Examples include BRCA1, the polymorphism predisposing women to breast and ovarian cancer, and DPD deficiency, a defect in the ability to metabolize certain chemotherapy drugs which results in lethal toxicity when they are given. Many other genetic polymorphisms are known, with more discovered every day. In some situation, the knowledge that one may carry such a polymorphism can be very useful.
There exist large databases in which one can trace geneology. Suppose I receive fluorouracil and almost die, and it is proven that I have congenital DPD deficiency. In the genetic info database, I add the fact that I have DPD deficiency. The program knows the inheritance pattern of DPD deficiency and can calculate the odds of carrying the mutation for each of my relatives. My second cousin (whom I do not know) can look herself up and find that she has a 20% chance of being DPD deficient as I am, and so decline to take fluorouracil, or ask to be tested. If she is tested and found not to be DPD deficient, she can add this information to the database under her own name. The risk for DPD of all of our common relatives can then be adjusted.
Such a database relies on two things: that people are truthful and information is accurate.-- bungston, Feb 01 2006 (?) DPD deficiency http://www.dpdenzyme.com/ [bungston, Feb 01 2006] 23andMe https://www.23andme.com/Genetics just got personal. [Cuit_au_Four, Nov 08 2008] In the oven http://www.personalgenomes.org/they flunked a deadline, but have not given up, yet [loonquawl, Mar 17 2009] Actually, it relies on one thing: that the information is accurate.-- bristolz, Feb 01 2006 ..and the information will never be accurate because the incidence of people being untruthful about medical matters, paternity and relationships is too great. Nice ideal though.-- ConsulFlaminicus, Feb 01 2006 Hypochondriacs would probably have a field day, once thye find out they have a 35% predispostion to develop _____.-- PollyNo9, Feb 02 2006 And then insurance companies will start turning you down for no obvious reason.-- moomintroll, Feb 02 2006 Iceland used to have a database of the DNA of all its citizens. It then got criticised for selling this, and the some complete genealogical records, to a genetics research company.-- hippo, Feb 02 2006 random, halfbakery