Ganko Suwa, known simply as Gabby in the US dub, is a minor character who only appeared in the episodes "The Cursing Camera" and "Small-size Nobita faces the Demon". She also appeared as a supporting character in Perman, one of Fujiko F. Fujio's works.
She is Perman's little sister in the original Perman anime.

(Source: Doraemon Wiki)