Zombie DNA Can Cause Muscular Dystrophy | Vanity Fair:
Here is something new and terrifying to worry about: zombie DNA. According to The New York Times, dead “junk” genes, basically thought to be dormant and harmless, are capable of becoming reanimated somehow and causing muscular dystrophy.
We have lots of dead genes left over from the process of evolution; the Times likens them to “broken and useless junk” in an attic. But some of the genes can apparently come back from the dead and cause facioscapulohumeral muscular dystrophy, or FSHD, which causes muscles in the shoulders and face to become progressively weaker. In some people, having fewer than 10 repeated copies of one particular dead gene causes FSHD—no one with more than 10 copies of the gene gets the disease.
It's not quite things that go bump in the night, but it's bad enough.