New gene associations in osteoarthritis: what do they provide, and where are we going?
OBJECTIVE
Osteoarthritis is a serious medical, social and economic problem affecting populations worldwide. Identifying susceptibility genes for osteoarthritis is a critical step in tackling this disease. The association study is today's most powerful tool for finding such genes, and the osteoarthritis research community has enjoyed initial success through the identification of several promising candidates. This review summarizes recent advances and emerging challenges in osteoarthritis association studies.


RESULTS
Replication studies have confirmed association of functional sequence variations in the secreted frizzled-related protein 3 (FRZB) and asporin (ASPN) genes with osteoarthritis. These studies have also prompted discussion of population-specific differences in reported associations. Association of several other promising genes with osteoarthritis, including LRCH1, RHOB, TXNDC3 and GDF5, await replication. The Human Genome Project and the International HapMap Project have established an infrastructure to support genome-wide association studies. Large-scale case-control association scans are underway, and genome-wide association scans are also beginning.


CONCLUSIONS
Due to initial success in confirming several susceptibility genes and the advent of the post-genome sequence era, this area of osteoarthritis study is expanding quickly. To overcome current challenges and to move on to the next stage, however, international collaboration based on a common platform is essential.
Ikegawa
Shiro
S
Laboratory for Bone and Joint Diseases, SNP Research Center, RIKEN, Tokyo, Japan. sikegawa@ims.u-tokyo.ac.jp
D016022:Case-Control Studies; D016326:Extracellular Matrix Proteins / Q000235:genetics; D020022:Genetic Predisposition to Disease / Q000453:epidemiology / Q000235:genetics*; D006023:Glycoproteins / Q000235:genetics; D016045:Human Genome Project; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins; D010003:Osteoarthritis / Q000235:genetics*; D010641:Phenotype; D020641:Polymorphism, Single Nucleotide; D000099274:Frizzled-Related Proteins
D016326:Extracellular Matrix Proteins; D006023:Glycoproteins; D047908:Intracellular Signaling Peptides and Proteins; D000099274:Frizzled-Related Proteins; C439889:ASPN protein, human