With GSDs the founder of the breed realized the Horand lines were overused in the beginning. 'Max v. Stephanitz recognized the danger inherent in close line breeding and changed his breeding program to outcross with minimally related dogs who were healthy and hardy with an excellent temperament. Like-minded breeders supported him in that they brought together utility dogs from distant branches of the diverse working lines and formed the highlines so advantageous to the breed. This was a significant contribution to the future development of the breed.'
This article shows some differences and the problems
http://showcase.netins.net/web/royalair/libreeding.htm