04 Sep 07

Whilst we all know that tall parents are more likely to have tall children, scientists have been unable to identify any common genes that make people taller than others. Now, however, scientists have identified the first gene, known as HMGA2, a common variant of which directly influences height.

The difference in height between a person carrying two copies of the variant and a person carrying no copies is just under 1cm, so does not on its own explain the range of heights across the population. However, the researchers believe the findings may prove important.

Previous studies have suggested that, unlike conditions such as obesity, which is caused by a mix of genetic and environmental factors - so called 'nature and nurture' - 90 per cent of normal variation in human height is due to genetic factors rather than, for example, diet. However, other than very rare gene variants that affect height in only a small number of people, no common gene variants have until now been identified.

The research was led by Professor Mark McCarthy from the University of Oxford, Dr Tim Frayling from the Peninsula Medical School, Exeter, and Dr Joel Hirschhorn from the Broad Institute of Harvard and MIT in Cambridge, US. Professor McCarthy Dr Frayling and were also part of a Wellcome Trust-funded study team that discovered the first common gene linked to obesity in April this year.

Using data from the Wellcome Trust Case Control Consortium, the largest study ever undertaken into the genetics underlying common diseases, and the Diabetes Genetics Initiative in the US, the researchers conducted a genome-wide study of DNA samples from 5,000 people. The findings - that variations in the gene HMGA2 make some people taller than others - were published online today in the journal Nature Genetics.

Each of us carries two copies of each gene, one from our mother and one from our father. However, each copy can be a variant, or 'allele' - in the case of the HMGA2 gene, a 'tall' version and a 'short' version. The researchers found that as many as 25 per cent of white Europeans carried two 'tall' versions of this particular gene, making them approximately 1cm taller than the 25 per cent of people who carry two 'short' versions.

The exact role that HMGA2has in growth is unclear, but the researchers believe it is most likely in increased cell production. This may have implications for the development of cancer as tumours occur due to unregulated cell growth. Previous studies have shown an association between height and certain cancers: taller people are statistically more likely to be at risk from cancers, including those found in the prostate, bladder and lung.

The authors believe that the study has major implications for helping scientists understand how common variations in DNA in the human the genome actually affect us, especially in relation to growth and development.

The research was funded by the Wellcome Trust with support from Diabetes UK, the Medical Research Council and a number of additional funders.