It's true that mutations don't give a huge amount of info about outcomes. However, as you said, it can be useful to know. You can go to this web address:
http://www.genet.sickkids.on.ca/Home.html
and search. I think the easiest way is to choose "search," then choose "text," and then enter the mutation number/letter combo. From my perspective, the more you know about every aspect of the disease, the better. Good luck!