Seeing as how they're the only 2 characters in JoJo that seemingly have the ability to turn invisible(at least on screen, u could theoretically make the argument for other characters), it's possible the 2 are connected by blood. Ik Risotto mainly uses his stand ability in order to turn invisible but who knows, maybe Shizuka has the same stand ability, maybe she manipulates iron 🤔.

Just a shower thought I had...