congenital radio ulnar synostosis: detection / prevention

only 1/5 cases have a had another family member with the condition. otherwise it's spontaneous. i have it, yet my sister does not. so there's no way to "plan" around it. i also have no supination in my left arm, and i have i "fibrous union" in my right arm i just discovered, but otherwise, it functions like a normal arm for the most part. I'm almost 16 and the pain came after an injury where my arm overextended. so i just suggest making sure that doesnt happen. don't let his arms get to fatigued, and avoid situations where he might have to overextend his arm or fall, in which case he'd have to catch himself with his hands (it's pretty painful) also make sure there's no compromise of the blood supply to his arm, that also causes severe pain. sorry this is so wordy, but i love helping anyone i can with my experience. best of luck