Estrangement
Neglect
noun, な adjective, の adjective
If your neglect of family members goes too far you'll end up with estrangement in your relationships with them. And they'll probably neglect you as much as you neglect them.
そえん
This is a jukugo word that uses the on'yomi readings of the kanji. You should be able to read this on your own.
それっきり、姉とは疎遠になっているんです。
With that, I became estranged from my older sister.