Not yet 5, he can hold seven-pound weights with arms extended, something many adults cannot do. He has muscles twice the size of other kids his age and half their body fat.
DNA testing showed why: The boy has a genetic mutation that boosts muscle growth.
The discovery, reported in Thursday's New England Journal of Medicine, represents the first documented human case of such a mutation.
http://www.cnn.com/2004/HEALTH/06/24....ap/index.html