Do You Have A Hichhicker Thumb?

I have what folks refer to as a Hitchhikers Thumb. The joint can bend backwards almost 90 degrees. Do you have this trait.

My son Brody was showing me his ability to bend his thumb back yesterday. He went on to tell me his teacher noticed it and "showed it to the other teachers". I'm assuming this is not a tremendously common trait. I also assume I passed it along to him. Do you have a hitchhikers thumb?

From http://faculty.stcc.edu

This trait is actually known as “Distal Hyperextensibility of the Thumb”, but that is too hard to remember!  This trait is distinguished by the ability to bend the distal joint of the thumb back as far as possible.  Some people can bend their thumb back as far as a 90 degree angle.  It is believed this trait is caused by a recessive gene (h), meaning (2) copies are required to display this characteristic.