The registration of white colored descendants of the German Shepherd Dog is more than complicated in the USA. We'll start with the history of the breed in order to help this all make sense.
When the white color fell into disfavor in German Shepherds, many breeders across the world began breeding away from the white color, and some even culled white puppies. Before the genetics were understood, it was believed that the white color was linked to health issues. However, in America, we continued to breed white colored German Shepherds even after most of the world had stopped. While AKC and the SV made white a disqualification in German Shepherds, UKC still permits white colored German Shepherds to this day. Eventually, in April 1999, UKC became the first all-breed registry to recognize a white descendant of the German Shepherd, which it then named the "White Shepherd." Keep in mind, when referring to a White Shepherd, I am referring to this UKC breed, and NOT the German Shepherd Dog - color white.
Fast forward a few years, and breeders in Europe began importing this American stock. They developed another breed standard, similar to the one written by UKC. Originally, the breed was to be called the "American/Canadian White Shepherd," but the name was rejected and the Swiss decided to dub it the "Berger Blanc Suisse" or "White Swiss Shepherd." The FCI did not grant full recognition to the White Swiss Shepherd until 2011.
Scouring the many pedigrees available on Pedigree Database, you will find that the vast majority of today's FCI registered White Swiss Shepherds can be traced directly some of the first UKC registered White Shepherds. It is also true that several of today's UKC White Shepherds can be traced directly back to FCI registered White Swiss Shepherds. To put it plainly, the UKC White Shepherd and FCI White Swiss Shepherd are the same breed. Now, I must add a disclaimer to this statement because it is possible to get AKC German Shepherd Dogs - colored white into the UKC White Shepherd studbooks through a loophole presented by AWSA. For this reason, it is important to make sure pedigrees are at least 3 generations clear of any non-white German Shepherd Dogs.
UKC registration as a White Shepherd does not and will never affect the standings of an FCI White Swiss Shepherd because FCI does not acknowledge or partner with UKC in any way. As far as FCI is concerned, UKC may as well not even exist. However, registering an FCI White Swiss Shepherd with AKC as a German Shepherd - colored white is not a type of dual registration. it is instead, a change of breed because FCI works with AKC. FCI reserves the right to have papers pulled from FCI White Swiss Shepherds registered as AKC German Shepherds via foreign registration (this does not apply to PAL or the Canine Partners Program because then the dog has not been entered into the German Shepherd Dog studbooks), because it is against the rules of the Circular 77/2007.
Writing off the UKC White Shepherd as separate from the FCI White Swiss Shepherd is harmful to the future health of the breed. Our breed has the luxury of having a set of dogs which didn't make it into the studbooks when they should have, but can now be used for genetic diversity. Unfortunately, while UKC accepts FCI, FCI does not accept UKC. For this reason, it is up to use breeders and owners to do everything we can to get UKC dogs into FCI for the health of the breed.