What role does ACTN3 play in longevity?

The ACTN3 gene variant (R577X) is primarily known for its association with athletic performance – the X-version is linked to endurance, the R-version to power and sprint ability. Regarding longevity, the evidence is weak and inconsistent. Some studies suggest a possible benefit of the X-variant for maintaining muscle strength in older age, while others find no significant effect. The provided context contains no specific data on ACTN3 and longevity. Therefore, this answer is based on general population genetics knowledge. It is important to note that ACTN3 is not an established longevity marker, and any effects, if they exist, are likely very small. The gene variant should not be used as a sole indicator of lifespan.