One tall gene

Call the National Basketball Association. Scientists report finding a gene for height.

The gene, HMGA2, comes in two versions. On average, adults with two copies of the “tall” version tower almost a centimeter over those with two copies of the “short” version. Adults with one copy of each version fall in between.

Past studies of twins pegged variation in height to be about 90 percent genetic. Diet and other unknown environmental factors account for the rest of the variation.

In the new study, Michael Weedon of Peninsula Medical School in Exeter, England, and his colleagues at other institutions scanned the genomes of nearly 34,000 people of European descent. Two single-letter DNA changes associated with the HMGA2 gene leaped out of the data as being most closely linked to height, the team reports online and in an upcoming Nature Genetics.

Although the scientists don’t know exactly how the gene affects height, it appears crucial for bone growth during gestation and childhood. Also, mutations in the mouse version of the gene are known to stunt the animals’ growth.

Many more genes influencing height remain to be found, say the researchers. They estimate that HMGA2 explains only 0.3 percent of all variation in human height.