[pharaohgeek]

Li-Fraumeni Syndrome is a genetic mutation of p53 that makes you more susceptible to various types of cancers. It's rare, in terms of number of people confirmed to have it, but is likely far more prevalent because it's not generally screened for. Interestingly, I'm told the reasons elephants don't (or rarely) get cancer is because they have 10 copies of p53, whereas humans only have 1.