Osteoarthritis and genetic link

In the first comprehensive study of the impact of genes on osteoarthritis of the hand in the U.S. white population, researchers found eight chromosomal regions indicating inherited risk for the disease. According to this study, which is published in the April 2002 issue of Arthritis & Rheumatism, susceptibility factors are likely specific for arthritis and could provide clues for new approaches for diagnosis or treatment.

"As part of the complex etiology of the disease, there is an increased recognition that a genetic component plays an important role," observes the study's chief researcher, Dr. S. Demissie of the Boston University School of Public Health. "Estimates of heritability range from 10 to 60% and may vary by the joint affected." She contends: "Searching for sites within the genome that accounts for variability in individual risk of osteoarthritis will provide insights to the most likely genes or cluster of genes that affect disease risk."

A leading cause of disability worldwide, Osteoarthritis (OA) is the most common form of arthritis and most prevalent among older adults. To effectively investigate linkages between the older parents and their middle-age children at an age when the disease can be easily detected in both, Dr. Demissie and her research team built on the work of The Framingham Study, a multigenerational study of OA that began in 1948. For its focused genome scan, the research team chose a random sample of 684 of the original Framingham participants and 793 of their offspring, including both fathers and mothers, both sons and daughters. The average age was 62 for the parents and 54 for the children. Fifty percent of the original participants and 30% of their offspring had at least one hand joint affected by OA.

Using the established Kellgren/Lawrence grading scheme, researchers compared the first hand radiographs of Framingham subjects with hand radiographs of their offspring. To ensure consistency of standards, one expert musculoskeletal radiologist read all of the hand radiographs, with films from parents and middle-aged children mixed.

As a result of their study, researchers identified eight chromosomal sites that may harbor genes for hand OA. The strongest evidence of genetic markers was found on two chromosomes: 7p and 11q.

"Further investigation of these regions using larger studies and finer maps will be important to confirm linkage," Dr. Demissie emphasizes.

Article: "Genome Scan for Quantity of Hand Osteoarthritis: The Framingham Study," S. Demissie, L.A. Cupples, R. Myers, P. Aliabadi, D. Levy, and D.T. Felson, Arthritis & Rheumatism; April 2002, 46:4, pp. 946-952.

For a full copy of the article, please contact David Greenberg at 212-850-6484 or by email at dgreenbe@wiley.com

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