How do I prevent my iPhone from wrongly auto-correcting a specific word?
Go into the keyboard settings and add a shortcut for the corrected spelling of the word.  I had to do this with my daughter's name, as every time I spelled it, it would come out in capitals.  You can just use a part of the word and it can auto spell the word for you, or you can spell it with a different capitalization and save the corrected version the other way.

If you need to use the first part of the word it may not work.  Don't really know, but it worked for me ;-)