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 Researchers on Sunday unveiled what they called the biggest such
study to date, analyzing genome data from more than a quarter
million people to identify nearly 700 genetic variants and more than
400 genome regions relating to height.
How tall or short a person becomes is estimated to be 80 percent
genetic, with nutrition and other environmental factors accounting
for the rest. The world's people on average have become taller over
the past few generations because of factors including improved
nutrition.
"We study height for two main reasons," said Dr. Joel Hirschhorn, a
geneticist and pediatric endocrinologist at Boston Children's
Hospital and the Broad Institute of Massachusetts Institute of
Technology and Harvard University.
"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," he said.
In addition, short stature in childhood is a major clinical issue
for pediatric endocrinologists. Knowing genes and their variants
that are important for height eventually may help doctors diagnose
children who have a single major underlying cause for short stature,
Hirschhorn added.
The international team of researchers analyzed data from the genomes
of 253,288 people of European ancestry, all from Europe, North
America and Australia. They perused about 2 million common genetic
variants in these individuals and identified 697 gene variants in
424 gene regions as related to height.
Many genes pinpointed in the study, published in the journal Nature
Genetics, are probably important regulators of skeletal growth, but
were not previously known to be involved, the researchers said.
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Some were related to collagen, a component of bone; a component of
cartilage called chondroitin sulfate; and growth plates, the area of
growing tissue near the ends of the body's long bones.
The researchers said there is much more to learn.
"We've found the genetic variants - the pieces of DNA that vary from
person to person - that account for 20 percent of the genetic
component to normal variation in height," said geneticist Timothy
Frayling of Britain's University of Exeter.
"This compares to a situation in 2007 when we knew absolutely
nothing about the genes and regions of the human genome involved in
normal height differences despite everyone knowing height is very
strongly genetic."
The team's previous 2010 study involved a smaller number of people
and identified 199 genetic variants residing in 180 genome regions.
"By doubling the sample size, we doubled the number of gene regions
that are connected to height, and greatly increased by about
seven-fold the number of actual genes where we can make a connection
to the biology of normal skeletal growth," Hirschhorn said.
(Reporting by Will Dunham; editing by Susan Thomas)
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