Scientists find breakthrough genetic link to height

An international team of researchers claim to have discovered a new gene that influences a person’s height. Scientists say that they have made a breakthrough by mapping the first gene that explains why some people are shorter in height.

The British and U.S. scientists at the Harvard University, the Children's Hospital Boston, Oxford University and the Peninsula Medical School in Exeter, who reported their findings Monday in the journal Nature Genetics, claimed that they have identified a single gene, called HMGA2, that could help determine if people will be taller or shorter.

The recently uncovered genetic link would likely enable parents to predict how tall their children will become, researchers said. "By defining the genes that normally affect stature, we might some day be able to better reassure parents that their child's height is within the range predicted by their genes, rather than a consequence of disease," said Co-researcher Joel Hirschhorn of Harvard Medical School.

It has long been known that genetic factors play a key role in determining a person's height instead of environmental factors such as diet, until now the common gene variants which affect the height of the majority of the population have remained a mystery.

An individual always has two copies of HGMA2, one from each parent. A person may either carry two 'tall' versions or two 'short' variants or one each. In the recent study it has been concluded that people having two 'tall' versions of the gene adds around a centimetre in their height compared to those with two 'short' variants. In the same way, people who inherit one copy of the "tall" genetic variant are about half a centimetre taller than those with none.

A single change in the recently found gene's DNA code can determine the variations in human height. The change of just a single base letter "C" (for cytosine) instead of a letter "T" (for thymine) in DNA sequence of HMGA2, adds nearly a centimeter (0.4 of an inch) in height to individuals who inherited this variant from their parents.

To reach their findings the team of researchers analyzed DNA from nearly 5,000 white people of European descent, mainly people living in Britain, Sweden and Finland.

After analyzing the DNA of participating individuals, the researchers found that nearly 25% of white Europeans carry the double "C" variant or “tall” versions of the gene, while a similar proportion have the two copies of the "T" or "short" version.

About 25 per cent of the white Europeans studied had two "tall" versions of the gene. The genetic variation is thought to increase the production of cells during early growth, and research on the genetics of height could have medical applications.

"Height is a typical 'polygenic' trait, in other words many genes contribute towards making us taller or shorter," another study author Tim Frayling of the Peninsula Medical School in Exeter, south western England said.

"Clearly, our results do not explain why one person will be six feet five inches (192 cms) and another only four feet 10 inches (145 cms). This is just the first of many that will be found, possibly as many as several hundred," he added.

With the recent breakthrough finding of the genes behind height, researchers hope to find clues about risks of various diseases that taller people commonly suffer with, including prostate, bladder and lung cancer.