If I do not respond to Amex request for 4506-t, will that affect the rest of my credit cards?

American Express froze / put a hold on my credit card and when I received a call, they said they need 4506-t signed and sent back to them because I am under review. My limit is low, I pay my payments, my credit is good. I do not feel comfortable sending them this information. If i do not send the information will anything besides my Amex be affected? If I do send them the 4506-t will the rest of my credit cards me affected? Amex is my lowest credit line card that's why i do not want to pay attention too much, but was wondering if any action on this will affect the rest of my cards.