Subject: Is there a way that a genetic disease, like porphyria, could contagious ?

I'm writing a story where porphyria somehow becomes contagious and spreads throughout the world, infecting almost 
everyone.  I don't know very much about science - s this even remotely possible due to some kind of mutation or some other 
reason?  Thank you for your help. 
Crystal

Re: Is there a way that a genetic disease, like porphyria, could contagious ?