This reminds me of a blog post in German [1] by a person who due to a software bug had been falsely diagnosed by 23andMe with limb-girdle muscular dystrophy. (Fortunately, he was able to identify that it was a misdiagnosis.) It appears that in this case potential misdiagnoses aren't just a theoretical problem.
[1] http://www.ctrl-verlust.net/23andme-wie-ich-fur-todkrank-erk...