So do I, but affects all of my joints pretty much. My fingers aren’t particularly double jointed but they do not pop, they just feel like they come out of their sockets when pulled. My shoulders are extremely hyper-mobile meaning I can make my shoulder bone pop out of my underarm...yes I know, you don’t wanna see that. It really freaks people out.  My daughter also has lax ligaments in her wrists and ankles, making them week. She is always getting hurt. I have an 18 yr old brother than can really do the one legged pigeon pose, with the heel of his foot on the top of his head. He is a big guy and weighs close to 200lbs! Not sure if it’s cah related, but I did wonder why it happens.

 I never heard of the trigger thumb either.