A common gene that influences height has been identified for the first time, helping to explain why some people grow taller than others.
People who inherit a particular version of the gene, known as HMGA2, are on average a centimeter taller than those who have a different genetic profile, scientists have found.
It has long been established that stature is heavily affected by a person’s genetic inheritance, which accounts for about 90 percent of the variation in height between people who have similar diets.
While the effect of HMGA2 is small, and tens if not hundreds of other genes are also involved in height, it is the first common gene shown to have a direct link. Very rare mutations that cause growth disorders have been pin-pointed before, but not genes that influence normal variation.
The gene was found by the same British team that discovered FTO, the first common gene known to contribute to obesity. Just as FTO is not a “fat gene”, HMGA2 is just one of many biological factors that affect height. It would not be possible to guarantee having a tall child by screening embryos for those with the “tall” variant, the scientists said.
Professor Mark McCarthy, of the University of Oxford, who led the research, said: “Like FTO, it has only a very small influence, and though it reinforces the idea that height is partly genetic it doesn’t mean we can start screening or genetic engineering to produce tall children.
“Quite apart from the ethical issues, it is only one of a number of genetic factors that are involved and the gene may have other functions too. We don’t know what the adverse effects of manipulating it might be.”
Everybody inherits two copies of HMGA2, one from each parent, and the gene comes in two varieties. About 25 percent of white Europeans have two copies of the “tall” version, and they are on average 1 centimeter taller than the 25 percent who have two copies of the “short” version, the scientists say.
The discovery, which is published in the journal Nature Genetics, has emerged from data collected by the Wellcome Trust Case Control Consort-ium, a British-led international project set up to identify common genes that contribute to disease.