My kitten walks on her toes

My kitten is 17 weeks old and since we got her at 8 weeks she has walked on her toes. She wobbles when she walks as well. She has been to the vet for shots and other things and we pointed it out. Our vet said she had no idea what it could be. She is not declawed. Her back legs are longer than her front like a Manx (she also has a stub tail like them so we think she is mixed). I don't know if it is genetic. All I know is my aunt took in a pregnant stray and it had at least three. One was missing its right front elbow or arm bone and another is, well my sister only said it was retarded. My kitten has full feeling in her limbs, shows no pain in them, it does not affect her at all but I worry it could get worse. Here are pictures of her back feet. Any idea what could be wrong?

I can't remember what that's called right now, but I've seen stories about it before. I know that it can be improved with splinting, though I'm not sure if that has to be done very young or if it would still help at her age. Maybe the vet can recommend a specialist?

With all the kittens in the litter affected, clearly there's been a genetic problem passed down or else the mother had an STD while pregnant :/. Hopefully she'll be spayed soon.

It's probable some kind of birth defect and as long as it's not bothering her I wouldn't worry too much about it. She may have tendons in her heals that are too short and won't allow her to set her whole paw down on the ground. If that's the situation she could have surgery ti fix it but it's normally not necessary. Ask what your vet thinks!