George Johnson is 3 years old and can't eat or drink. His condition is so rare that doctors don't even know what is wrong with him. He's been in and out of hospital all his life, and has had more than 50 operations.
He's been at Great Ormond Street hospital in London since November to see if they can help him. Our reporter Mel Barham went down to the capital to see them. For more information go to Team George's facebook page.