Assuming that you know what you have done, this is the very first case, not only in this G2 subforum but entire XDA site, that I've heard installing custom ROM and lost root.
Official CM10.1 Nightly @ 1000MHz NOOKcolor
Offiical CM11 KK Nightly on Kindle Fire 1st-Gen
Rooted Kindle Fire HD 8.9" w/ Nova Launcher
Virgin JB 4.3 on Sony Xperia Tablet Z
Stock ROM KK 4.4.2 on LG-D800
Virgin Samsung Galaxy Tab 2 10.1 - LOST
Slimbean 8.1 on Galaxy S2 i777 - LOST