My 16 yr old son lives wit his uncle he has tepary custudy mother sign her rights away my son is un happy and wants to live wit me the uncle threats my son if he says anything want answer my calls

First, a mother can't just sign her rights away. Only a court can terminate rights. If that did happen what were the circumstances? Why did the uncle get custody and not you? How long ago did this happen?

The pat answer is you get an attorney and file for custody. But for us to help further we need to understand the situation better so you need to provide more details. ANY question on law needs to include your general locale as laws vary by area.

As Scott said very well - need more details BUT you can always go to Court and request custody. It is not your son's choice.