This may be a 'scientific urban legend', but I seem to recall reading about a man who had a defective pituitary gland-he was a dwarf,less than 4' 5". Then in his twenties he suffered a head injury, which put his pituitary gland into hyperdrive...He grew to 5'0"...5' 6"..6'...And he kept on growing till he was a little over 7', when his overstrained body gave out. So gvoes the tale, anyway, which I read in either Guiness or a Guiness copycat book of records.