In a study published online in the March issue of Nature Genetics, a group of Japanese scientists presented results that point to a variant in a gene called GDF5 that is related to the development of osteoarthritis, the most common form of arthritis. The team was lead by Shiro Ikegawa of the SNP Research Center in Tokyo.

The GDF5 gene is closely related to the subfamily of bone morphogenetic proteins known to be involved in joint formation. For this study, the team analyzed variations across the GDF5 gene and found one particular variant was significantly more frequent in two independent populations of Japanese individuals with osteoarthritis of the hip compared with disease-free individuals. To examine the variant’s particular association with hip arthritis, the team sequenced DNA from 24 afflicted individuals and searched for variations in the genetic coding called SNPs, or single nucleotide polymorphisms.

The same variant was also found to be significantly more frequent in Japanese and Chinese individuals suffering from osteoarthritis of the knee. The variant was to confer 30 percent to 80 percent additional risk of developing the disease. This particular mutation is believed to reduce the amount of GDF5 produced, leaving joints most prone to “wear and tear.”

The study is careful to note that the links established between the genetic variant and arthritis applied only to Asian populations.