I'm not sure if this would be a similar thing or not...

Albino horses are not common either. Most "white" horses are actually gray. They have to have all pink skin to be called white, most white haired horses still have gray skin. Some "white" (which they now call cremello) horses have blue eyes. It is very rare to see one that has pink eyes. I am pretty sure the pink skin, pink eyes is the true albino. Maybe it's like that for frogs too? They could look albino but with the blue eyes, making them not exactly albino?

A thought anyways.

Edit: Ok I'm a bit off on that lol. I'm not sure if horses can even get pink eyes. But there's still different variations of whites/grays/cremellos.

http://en.wikipedia.org/wiki/White_%28horse%29