Scientists discover 'tall gene'

British scientists have discovered the first genetic link to height, according to a study published in the journal Nature Genetics last week. The study shows that a single letter change in the DNA sequence of a gene called HMGA2 can boost a person's height by around one centimetre.

It has long been known that tall parents are more likely have tall children and vice versa, suggesting that genes have a strong influence on height. Although height is thought to be 90 per cent down to genetics, scientists have previously had difficulty in identifying the hundreds of genes thought to be involved, in the absence of new technology which allows the entire genome of thousands of people to be analysed.

Dr Timothy Frayling of Peninsula Medical School in Exeter, who led the research, hopes that a better understanding of the genetic basis of height will be reassuring to parents. 'For a lot of children who perhaps are a bit behind their growth chart, there is a pressure for doctors to treat them or find something wrong with them,' he said. 'If we can find 50 or 100 height genes, we could look at them and say 'this is entirely in keeping with your height profile'.

In the hunt for the gene, the researchers began by scanning the entire genome of 5,000 people to identify single letter changes linked to height differences, leading to the discovery of a tiny variation the HMGA2 gene. Next they looked for the same variation in another 29,000 people, confirming that the gene variant is linked to height.

With a few exceptions, we inherit two copies of each gene, one from each parent. The researchers found that people who carry two copies of the 'tall' version of the gene are an average of one centimetre taller than people who carry two copies of the 'short' version. Those who carry one of each are somewhere in the middle.

Dr Frayling believes that the HMGA2 gene is just the first of many genes which will be discovered in the future. 'We won't expose all of the genetic basis of height, but over the next couple of years, we might find several hundred [genes] - perhaps 50 per cent of the variation', he said.