Genes and lupus: The basics
Lupus is a complex disease that is likely caused by several interacting features. For example, we know that inherited genes, environmental exposures (such as certain medications, severe exposure to ultraviolet rays, perhaps certain viral exposures at key times), and female hormones all likely contribute to the development of lupus.
No single gene or group of genes has been proven to cause lupus. Lupus does, however, appear in certain families, and when one of two identical twins has lupus, there is an increased chance that the other twin will also develop the disease.
These findings, as well as others, strongly suggest that genes are involved in the development of lupus.
The majority of lupus cases that develop are what is called sporadic, however—that is, no known relative has the disease. Although when lupus develops in people with no family history of lupus, there are likely to be other autoimmune diseases in some family members.
Certain ethnic groups (people of African, Asian, Hispanic/Latino, Native American, Native Hawaiian, or Pacific Island descent) have a greater risk of developing lupus, which may be related to genes they have in common.
Q/A: Common questions about genes and lupus
What if my mom or siblings have lupus? Will I develop it, too?
- People are more susceptible to developing lupus if they have immediate relatives with the disease, but that doesn’t mean they will. In fact, most don’t, says Lindsey Criswell, MD, MPH, chief of the Division of Rheumatology at the University of California, San Francisco. Even if a person with lupus has an identical twin, there’s only about a 50 percent chance the undiagnosed twin will develop it.
What if the medical experts find all the gene variations that are linked to lupus? Can’t they just change the person’s genes to prevent him or her from developing the disease?
- Probably not, says Courtney Montgomery, PhD, associate member of Oklahoma Medical Research Foundation in Oklahoma City. The goal of genetic research is to improve outcomes for people with lupus, not change their DNA. “Besides, we fear that if we alter the DNA code to fix one thing, there may well be unexpected, negative consequences elsewhere,” she says.
What if I have lupus, and a family history of lupus? What do I tell my daughter?
- When she hits puberty, take her to a rheumatologist for blood tests and autoimmune antibody levels. Get the baseline information and watch her very closely, Montgomery says. Lots of family members may have abnormal antibody levels and never get sick. But they can still pass on genetic variations and the predisposition for lupus. Normally we tell young women with lupus that the risk of their child developing the disease is very small: 1 to 5 percent.
What should I do if lupus runs in my family?
- Currently, no screening or genetic tests are available. We encourage family members to lead active, healthy lives. Sunscreen protection is always a good idea. If symptoms develop (joint swelling and pain, unexplained rashes, atypical chest pain), we encourage family members to seek evaluation from their regular doctors, and to be sure to mention the family history of lupus.
I have lupus, should my children be tested?
If your children show no symptoms of lupus, checking for autoantibodies in the blood (ANA, double-stranded DNA, and others) will not be an effective screen for the presence or absence of lupus. While there is a high likelihood that a mother with a positive ANA test will predispose a child to have a positive ANA, the ANA test alone is not helpful without other signs or symptoms of lupus.
ANA testing is not advisable in individuals who do not have symptoms, and we highly discourage testing children for lupus since doing so in the absence of lupus signs or symptoms usually causes undue concern or alarm.