700 genetic variants influencing height identified

Scientists have identified nearly 700 genetic variants that are involved in determining height.
The study, from the international Genetic Investigation of Anthropometric Traits (GIANT) Consortium, is the largest of its kind to date and nearly doubles the number of known gene regions influencing height to more than 400.
Researchers examined data on DNA from more than 250,000 people to identify a fifth of the genetic factors that cause height to vary between individuals.
"Height is almost completely determined by genetics, but our earlier studies were only able to explain about 10 per cent of this genetic influence," said Joel Hirschhorn, of Boston Children's Hospital and the Broad Institute of Massachusetts Institute of Technology and Harvard, leader of the GIANT Consortium and co-senior investigator on the study.

"Now, by doubling the number of people in our study, we have a much more complete picture of how common genetic variants affect height - how many of them there are and how much they contribute," he said.
The GIANT investigators, numbering in the hundreds, shared and analysed data from the genomes of 253,288 people.

They checked about two million common genetic variants (those that showed up in at least 5 per cent of their subjects).
From this pool, they pinned down 697 (in 424 gene regions) as being related to height, the largest number to date associated with any trait or disease.

"In 2007 we published the first paper that identified the first common height gene, and since then the research has come on leaps and bounds. We have now identified nearly 700 genetic variants that are involved in determining height," said co-senior investigator Timothy Frayling, of the University of Exeter, UK.
Many of the 697 height-related genetic variants were located near genes known to be involved in growth.
"Many of the genes we identified are likely to be important regulators of skeletal growth, but were not known to be involved until now," said Hirschhorn.
"Some may also be responsible for unexplained syndromes of abnormal skeletal growth in children," he said.

For example, the mTOR gene is well known to be involved in cellular growth, but had not previously been connected with human skeletal growth.
Other genes confirmed as important include genes involved in metabolism of collagen (a component of bone) and chondroitin sulfate (a component of cartilage), as well as networks of genes active in growth plates, the area of growing tissue near the ends of the long bones.
The findings are published in the journal Nature Genetics.