I just found a manx cat and I'm worried he has Manx Syndrome

Hello
I just took in what I believe is a manx cat. He has been neutered and I assume was someone's pet, but we cannot locate his owner. I took him to the vet and she says he is healthy but I am afraid he may have manx syndrome. He is between 1 to 2 yrs old and has no problems walking, he's s little bowlegged, but he does have issues with his bowels. He seems happy and is playful but I am still concerned with his condition. I read that they don't live long if they have manx syndrome. He is so sweet and loving and I just wondered if anyone can give me some insight on what to expect. Thanks for any help with my little Bob (short for Bobtail :) )

I also added this to http://www.vetlocator.com's Ask A Pet Pro

Jessica