Timo, I did not check MA, because I did not expect a quick update. 99 Pegasi is fictional, which is too bad. A little work and they could have found a DS star that is real.Memory Alpha now has that down as "a triple-mode, high-amplitude Delta Scuti". Hard to tell if that's "correct" since 99 Pegasi is fictional... A quick googling reveals no DS variables in Pegasus ITRW.
EDIT: Belay that. GX Pegasi is a DS variable, 408 ly from Earth.
Timo Saloniemi
GSC 03144-595, A NEW TRIPLE-MODE RADIALLY PULSATING HIGH-AMPLITUDE δ-SCUTI