I often thought about that. Unlike most every character in ST, Kira has her family and home right next door all the time. Yet we never really saw much of it or heard about them.
Not just her siblings, but cousins, uncles, everyone. She never seemed to get together with them for all her Bajoran holidays and celebrations, never mentioned going to Bajor to visit them (oh sure, Bareil and Shakaar...)
I don't know. Go figure.