Notably, the TV special's lineup doesn't include original cast members Nia Sioux, Maddie Ziegler and Mackenzie Ziegler. In a YouTube video, the latter siblings' mom, Melissa Gisoni, addressed why they didn't go to the reunion. "It was a choice," Gisoni said. "And my girls -- you know, mental health is talked about everywhere, which I think is so fabulous -- and they just didn't want to do it." She said Mackenzie and Maddie are "very close with a lot of the girls." According to a report from People, multiple girls didn't want Miller at the reunion, and she wasn't asked to be there.