What is the Role of Heredity in Risk for Arthritis?
There are several types of arthritis that tend to occur more often in certain families. Environmental factors also influence the onset of arthritis, however, thus the precise impact of heredity is hard to quantify.
When a disorder “runs in a family,” that means that more than one person has had the condition. The likely cause can be any of three possibilities:
A gene mutation is being passed to other family members
A behavior pattern is being learned, for example, overeating and not exercising, or
A combination of both
When genetics professionals assess family history, they ask about first-, second-, and third-degree relatives. First-degree relatives would be parents or children and sisters or brothers. Second-degree family members would be grandparents and grandchildren, aunts and uncles, nieces and nephews. A third-degree relative would be a first cousin. Let’s consider what is known about heredity and various types of arthritis by referring to the Genetics Home Reference in the US National Library of Medicine, National Institutes of Health.
1. Ankylosing spondylitis (AS) can occur in more than one person in a family, but is not purely genetic. Rather, it blends genetic and environmental factors. How do they know? There is an association between having the HLA-B27 biomarker, and yet 80% of those who inherit the biomarker will not get AS.
2. Rheumatoid arthritis (RA) also is believed to be a combination of genetic and environmental factors. While there is an association with the human lymphocyte antigen (HLA) genes, particularly HLA-DRB1, environmental exposures such as smoking and viral and bacterial infections also increase risk for RA. Having a family member with RA increases risk but is not the sole factor in predicting susceptibility.
3. Psoriatic arthritis (PA) is more likely to be acquired in the presence of variation of specific HLA genes. About 40 percent of people with PA have at least one close relative with psoriasis alone or PA, but a combination of genetic and environmental is believed to influence whether one acquires PA.
This indicates the wisdom of controlling one’s environmental risk factors to the best of his or her ability if any type of arthritis is prevalent among family members. If there’s a genetic risk, it can’t be changed. But many environmental risks can be controlled. For example, maintaining a healthy weight, following a nutrient-dense diet, and engaging in regular low-impact physical activity might prevent the onset of arthritis even if a genetic factor is present.
Many chronic diseases are correlated with obesity, resulting from an unhealthy diet and inactivity. The rewards of resisting temptation are good health and quality of life. People who have arthritis need to know that it’s never too late to make changes. Regular physical activity and weight loss can put less stress on joints and improve quality of life.