This week's new papers
Here’s what we told the world’s journalists last week. You can use Google News to see what they made of our briefing.
Please cite Nature Genetics as the source of the following items. If publishing online, please carry a hyperlink to http://www.nature.com/naturegenetics.

A variant in a gene called GDF5 is associated with the risk of developing osteoarthritis
DOI:10.1038/ng2005
Osteoarthritis is the most common form of arthritis, affecting more than 20 million people in the United States. The disease is caused by the breakdown and loss of the cartilage in one or more joints during ageing, leading to swelling, pain, and limited mobility. Shiro Ikegawa and colleagues analyzed variation across the GDF5 gene and found that one particular variant was significantly more frequent in two independent populations of Japanese individuals with osteoarthritis of the hip compared to disease-free individuals. The same variant was also found to be significantly more frequent in both Japanese and Chinese individuals suffering from osteoarthritis of the knee. Depending on the study, the variant conferred 30%-80% additional risk of developing the disease. The authors showed that this variant probably reduces the amount of GDF5 produced. As GDF5 is a protein that is secreted by cells and is known to be involved in cartilage development, lower levels of GDF5 may affect the maintenance of cartilage in joints.