Re: chromosome disorder??
I can't begin to guess what your son might have, but I can try to explain what it means about the extra piece of the chromosome. It is a little difficult on the computer, but I'll try.
Let's say that these are your two x chromosomes:
Now, normally each child has a 50/50 chance of getting one of your X chromosomes.
Now lets say one of your X chromosomes breaks a little, and then it accidentally reforms with the other one. Now you have:
So now you still have all your genetic material, so there is no problem for you. But if your child gets the X on the left, they have too much material, and if they get the one on the right, they don't have enough. This is why they need to determine if it genetic.
Some women who have multiple spontaneous miscarriages have this sort of problem with their chromosomes.