People with a certain gene version (TT) might not develop their brain's wiring the same way as others as they age — especially in how it changes in young adulthood and later life — possibly because of how their bodies make certain fats.

What we've found so far is that the evidence leans toward the idea that having the TT genotype of the FADS2 rs174583 SNP may be linked to differences in how white matter in the brain develops over time in healthy White individuals [1]. Our analysis of the available research shows this pattern, but we do not yet have a complete picture. We reviewed one key assertion from the data, which suggests that people with the TT genotype might not develop their brain’s wiring—known as white matter—in the same way as those with other genotypes, particularly during critical periods like young adulthood and later life [1]. This possible difference could be tied to how the body processes or produces certain fats, which are important for brain structure and function [1]. The evidence supporting this idea is rated as 61.0 support and 0 refute, based on the assertions we analyzed. Still, we want to be clear: this is a narrow view based on limited assertions. We are not saying this effect definitely happens, nor are we claiming it applies to everyone with this genotype. Our current analysis only shows that the evidence we’ve reviewed so far leans in this direction. We also cannot say how strong this effect might be, or at what exact ages it appears. There may be other factors—like diet, lifestyle, or additional genes—that play a role, but the evidence we’ve seen so far does not address those. Practical takeaway: If you’re a healthy White individual with the TT genotype, the current evidence we’ve reviewed suggests your brain’s white matter might develop differently over time—possibly due to fat metabolism—but we don’t yet know what that means for thinking, memory, or brain health in daily life.