Researchers uncover new piece to the puzzle of hu...(ccount for less than 1 percent of human ...)

Specifically, the newly identified genetic variant is associated with an average difference in height of about 0.4 centimeter (cm), or a little more than an eighth of an inch. The exact effect ranged from 0.3 cm to 1.4 cm (0.12 to 0.55 inches), depending upon the population and whether an individual has one or two copies of the taller version of the variant. No differences in the effect were detected between males and females, nor did the variants appear to be associated with weight or body mass index.

Many of the genetic variants involved in height likely will have only small effects, so its going to take a lot of work involving very large sample sets to uncover all of them, said National Human Genome Research Institute (NHGRI) Director Francis S. Collins, M.D., Ph.D., one of the studys co-authors and an investigator in NHGRIs Genome Technology Branch. But it is very exciting to have powerful enough tools to succeed at this extremely difficult work. Our findings show how understanding the factors involved in human height may provide new insights into osteoarthritis and other musculoskeletal diseases.

Osteoarthritis is by far the most common type of arthritis, affecting nearly 21 million Americans. The degenerative joint disease, which primarily affects cartilage, is seen mostly among older people.

The researchers speculate that genetic variants that reduce production of the GDF5 protein may affect the amount of cartilage in the spine, the proportion of limbs and/or the angles of joints, resulting in both a modest decrease in height and increased susceptibility to osteoarthritis.

To make their findings, researchers used a genome-wide association study, which is a relatively new, comprehensive strategy that utilizes the tools made possible by the sequencing of the human genome and the mapping of human genetic variation. To conduct a genome-wide association study o
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