What Causes Thumb Without Joints?

I was born with no joints in my thumbs. Literally they are just straight bone, no joint or wrinkles on my thumb and also no muscle developed at all in the left lower corner of my palm. I actually was just made aware that this is not normal at all. And lately it has been giving me more problems just with pain and flexibility. I'm just wondering if you know what this is called and some information about it if any...what caused this if known and if it can be treated or could have been earlier on.