While in hospital (Getting a bone graft for my cleft), I thought about this subject briefly, and came to the conclusion that if it was genetic, as in his whole family had been cripeled and it had become a part of thier DNA structure (Unlikely), then the alien would be crippeled, but other than that, I have started to doubt that it would be cripeled. Maybe a 70/30 chance that it wouldn't be.
Zombie to English/english to zombie translator http://www.siddhant.name/games/ud/english2zombie.html