New Research Uncovers One-Fifth Of The Genes Responsible For Height In Humans

Chuck Bednar for redOrbit.com – Your Universe Online
Subtle changes in our DNA could help explain why some people are taller than others, the international team of researchers behind the largest genome-wide association study ever conducted report in the October 5 edition of the journal Nature Genetics.
Scientists from more than 300 institutions representing the Genetic Investigation of Anthropometric Traits (GIANT) Consortium reviewed data from more than 250,000 subjects and identified nearly 700 variants of genome-wide significance that together explained 20 percent of all adult height. Their findings nearly double the number of known gene regions influencing height to over 400 and provides new insight of the biology of this particular trait.
“Height is almost completely determined by genetics, but our earlier studies were only able to explain about 10 percent of this genetic influence,” GIANT Consortium Leader and co-senior investigator Dr. Joel Hirschhorn from Boston Children’s Hospital and the Broad Institute of MIT and Harvard said in a statement.
“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 added.
Dr. Hirschhorn and his colleagues reviewed nearly two million common genetic variants (i.e. those that showed up in at least 5 percent of their subjects) and found 697 variants in 424 genetic regions as being affiliated with height.
Co-first author Dr. Tonu Esko of Boston Children’s Hospital, the Broad Institute and the University of Tartu (Estonia) added that, in the wake of their research, his team can now explain approximately 20 percent of the heritability of height – an eight percent increase from where scientists were prior to the Consortium’s work.
According to Reuters reporter Will Dunham, many of the genes identified in the study are believed to be key regulators of skeletal growth that had not been previously linked to height. Some were related to the bone component collagen, some to the cartilage component chondroitin sulfate and others to growth plates (tissues near the ends of the body’s long bones).
Studies have suggested that up to 80 percent of the factors responsible for determining height lies in our genetic code, but it was only seven years ago that the first genes associated with the characteristic were discovered, according to BBC News. Much work must still be done, but experts believe this study could ultimately lead to a simple test to quell parents’ fears about their children’s growth.
“We study height for two main reasons,” Dr. Hirschhorn, a geneticist and pediatric endocrinologist, told Dunham on Sunday. “For over 100 years, it’s been a great model for studying the genetics of diseases like obesity, diabetes, asthma that are also caused by the combined influence of many genes acting together. So by understanding how the genetics of height works, we can understand how the genetics of human disease works.”
“It’s common knowledge that people born to tall parents are more likely to be tall themselves. Most of this is down to the variations in our DNA sequence that we inherit from our parents – the different versions of all our genes,” Professor Tim Frayling of the University of Exeter Medical School said in a statement. “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.”
He added that their new study “goes a long way towards fulfilling a scientific curiosity that could have real impact in the treatment of diseases that can be influenced by height, such as osteoporosis, cancer or heart disease. It also a step forward towards a test that may reassure parents worried that their child is not growing as well as they’d hoped – most of these children have probably simply inherited a big batch of ‘short genes.’”
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