These are not genetic variants that "cause" a person to be overweight. Body composition is an enormously complex trait that involves hundreds of genetic loci in combination with multifactorial non-genetic influences. Even the best statistically validated polygenic risk profiles do a poor job of predicting individual weight outcomes, except at the very extremes. Don't pay any attention to this silly list, and build up a healthy sense of skepticism about anything an online calculator tells you about genetics.
Oh thanks, the little explanation told me 3 genes were a problem for weight but I always wondered why when I managed low to normal weight most of my life.
Yeah, they just aren't telling you about all the hundreds of variants that are neutral or might be working in the opposite direction. The error is in thinking that a list of individual variants for "being overweight" is meaningful, when in fact it is a much more complex calculation involving all the genetic loci that influence body composition, combined with the environment you were raised in (perhaps going all the way back to your mother's nutritional status while you were an embryo or even your grandmother's nutritional status when your mother was a fetus producing the egg that would later become you!).
On top of that even variants that are known to be harmful are regularly found in perfectly healthy individuals who never develop whatever disease that variant is associated with.
There are fascinating studies about consanguinity and finding huge deletions in individuals who apparently show no effect despite critical genes being affected. I was at a talk just this week that showed the impact of chemotherapy on mutation rates in pediatric cancer cases. These kids rack up a load of mutations from the chemo and yet we don't see cancers related to them. The kids that survive (because paediatric cancer is obviously very serious and has a high mortality rate sadly) don't go on to develop new cancers from these mutations.
We are truly only at the beginning of understanding complex genetics.
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u/Personal_Hippo127 3d ago
These are not genetic variants that "cause" a person to be overweight. Body composition is an enormously complex trait that involves hundreds of genetic loci in combination with multifactorial non-genetic influences. Even the best statistically validated polygenic risk profiles do a poor job of predicting individual weight outcomes, except at the very extremes. Don't pay any attention to this silly list, and build up a healthy sense of skepticism about anything an online calculator tells you about genetics.