Hokkaido breed is highly susceptible to CEA because of the known CEA-associated mutation much like the Collie-related breeds.
About CEA: http://www.optigen.com/opt9_test_cea_ch.html
USA OptiGen Abstract study on CEA in Hokkaido dogs:
Are you saying it is OK to breed from Carrier dogs?
Definitely yes, under controlled conditions. Following discussion with the experts in genetics, it was recognised that controlled breeding from CEA Carrier dogs could be of benefit to the genetic strength of the breed while ultimately permitting eradication of the atypical CEA gene. Most all animal geneticists will point out that it is very bad for a breed’s health to "ban" a single gene characteristic as this can easily lead to unforeseen consequences.
(Source: International Sheep Dog Society)