I have a guy on my pool team almost like that. His "birth defect" is in between the wrist and elbow. Was that way from birth. He shoots VERY well. Holds the cue with that "hand". Has not held him back at all.There was a very strong player/hustler out of Muskogee, OK that they called "Little Hand." I believe his real name was Lewis Bramlett. He had one arm that was very short and withered at the end, with maybe a small thumb and two fingers. It was like he had no elbow, just a forearm growing out of his shoulder. I can't remember now if he held the cue with that small arm (I think so) or used it as his bridge hand. Either way, he was severely handicapped for playing pool, and yet he was an excellent player. I watched him dismantle one of Oklahoma City's top bar table players, Herman the German, one night in OKC for $25 a game, when that was serious money. I sat there in amazement watching this man run out rack after rack.