This is a strange one, to be sure.  The lycanthropy isn't spread by a virus/bite or genetically, but only through a deliberate curse that can be put on anyone if that person accepts it.

That said, this is the story of a 12 year old boy named Zach who grows up in a family of werewolves, and yet he can't bring himself to accept that kind of life for himself.  They won't take no for an answer, and he ends up running away from home after they've already performed the first part of the curse on him, and barely three days before he'll be expected to make his first kill and complete the process.

He scrapes by on the little money he can make, always in fear of being found and caught, until he reaches his uncle's house in Texas.  There he finds shelter. . . and a box of silver bullets in the closet, just in case.  The story is ultimately a tale of love, and of the sometimes high cost of doing what we believe is right.

The story has a mild Christian flavor, which also makes it rather unusual for a werewolf book.  But it fits together remarkably well, and the story is really captivating.  I know it's for sale on Amazon and maybe some other places but I'm not sure where else.

You can also read the first half of it for free on the author's website, which is at:

www.williamwoodall.org/cryforthemoon.aspx