Mr. Universe Jr.: Child’s gene mutation confirms protein’s role in human-muscle growth

Find the kid a sports agent. Researchers studying an unusually muscular tot have found that he has gene mutations similar to ones that produce abnormally brawny cattle and mice. Less-severe variations in the same gene may underlie the success of some athletes, the scientists speculate.

The boy’s mutations disrupt both copies of the gene encoding a muscle protein called myostatin.