Hypermobility/hyperextension of knees

I suffer from hyperextension of the knees--I was born with this.  I believe to about the -10 or -15 degree mark--it has been a long time since it was measured.  This has quite affected my posture, tilting my pelvis forward, throwing my neck back etc.  It has begun to make my knees hurt, hips hurt and lower back hurt.  I also suffer from chronic severe headaches and I'm pursuing the possiblity of cervicogenic headaches.

Does anyone else suffer from the hyperextension, being born with it (recently heard the term Ehlers-Danlos syndrome?), not from injury?  Can it be corrected?  How is that done?

Thanks
Leslie