My sister has a cat with this same problem. Only, she wasn't born with it. She's now 2 years old and developed it after surviving Distemper and high fevers as a little kitten. It sure doesn't stop her. She may not be able to jump up onto the kitchen counter like the other kitties in the house, but she finds ways to climb up onto the sofa, the coffee table, and anything else. Her nickname is Miss Stumbles.