The German toddler is supposedly the first human known to have the myostatin mutation (or, rather, to have two copies of it), but Double muscling in cattle due to mutations in the myostatin gene reports “that the myostatin gene is highly conserved among vertebrate species and that two breeds of cattle that are characterized by increased muscle mass (double muscling), Belgian Blue and Piedmontese, have mutations in the myostatin coding sequence.”
Muscle: The Myostatin Connection discusses the knock-out mice and at least one human case of the mutation:
The ultimate demonstration that myostatin regulates muscle size in humans is the work of a man named Victor Conte of BALCO laboratories. He has shown that champion bodybuilder Flex Wheeler actually possesses a mutation that has resulted in the deletion of his myostatin gene (much like that in Belgian Blue Cattle). This goes on to prove something else that has always been suspected…that champion bodybuilders possess some sort of genetic gift that allows them to become much more muscular than the average person. It seems that champion bodybuilders may owe much more to their genetics than they do to their training, supplement or drug use.
Flex was a participant in a study we recently conducted in collaboration with the Department of Human Genetics at the University of Pittsburgh involving 62 men who made unusually large gains in muscle mass in response to strength training (extreme responders). Flex was one of only nine extreme responders that had the very rare “myostatin mutation.” Myostatin is the gene that “limits muscle growth.” Specifically, Flex had the rarest form of myostatin mutation at the “exon 2″ position on the gene. This simply means Flex has a much larger number of muscle fibers compared to the other subjects or the normal population. We believe that these are the very first myostatin mutation findings in humans and the results of this landmark study have already been submitted for publication. Flex was also found to have a very unusual type of the IGF-1 gene. In fact, Flex was the only participant in the study that did not have a “match.” All of the other extreme responders had at least three other subjects with a matching IGF-1 gene. Based upon Flex’s very unique genetic profile, we plan to expeditiously publish a scientific paper that reveals his complete genotype in specific detail. The publication of his remarkable genetic data should generate an enormous amount of media exposure.