In early February, my sister Peggy alerted me that she had spent the extra money for the health information available with a DNA test on Ancestry.com. She learned that she carries two mutations that can lead to hemochromatosis, a disorder in which the body stores too much iron. I clicked the button on 23andme.com to get my health results and they were the same. Two tests were available to determine if the condition was active: Peggy and I are negative on both tests. We do not have the disease and we have both decided to donate blood regularly because, if we had the disease, phlebotomy would be the only treatment.
Now the good news. I also carry two GOOD mutations that bestow fast-twitch muscles.
This report is based on a genetic marker in the ACTN3 gene. This marker controls whether muscle cells produce a protein (called alpha-actinin-3) that’s found in fast-twitch muscle fibers. While some people don’t produce this protein at all, almost all of the elite power athletes who have been studied have a genetic variant that allows them to produce the protein. This suggests that the protein may be beneficial at least at the highest levels of power-based athletic competition.
ACTN3: More than Just a Gene for Speed
One of the most promising genes in that regard is ACTN3, which has commonly been referred to as “a gene for speed”.
Studies have found that most elite power athletes have a specific genetic variant in a gene related to muscle composition called the ACTN3 gene. This variant causes muscle cells to produce alpha-actinin-3, a protein found in fast-twitch muscle fibers.