There is a white cat breed – the Khao Manee
(Chicago, Illinois, USA)
I noticed that it is sometimes said there are no white cat breeds, but there is one — a rare breed from Thailand called the Khao Manee.
It is thought this may be the same as the “Khao Plort” from the Tamra Maew cat poems written centuries ago, which also described cats corresponding to the more well known breeds of Thai origin the Siamese, Burmese and Korat.
The Khao Manee is the most recent of the Thai breeds to come out of Thailand; it has only been in about the last decade that it has been imported to Western countries. It has won limited acceptance in GCCF (to register the cats) and as of September 2011 was elevated to a Preliminary New Breed in TICA.
I just searched and noticed that you do have an article on the KM on this site, http://pictures-of-cats.org/khao-manee.html which also has some very good info in the comments from the secretary of the KM Cat Club.