Family Links and SLE
By A. G. Moore
July 11, 2013
Diagram of Human Chromosome 6, one of the chromosomes implicated in lupus transmission
Image by: Pdeitiker on Wikimedia Commons
Do family members of lupus patients have an increased risk of developing the disease? This is a question most patients ask their doctors at some point. The response they receive is likely to be vague.
While first degree relatives (siblings, parents, children) of lupus patients do tend to develop the disease at higher rates than the general population, this experience varies depending on circumstance. For example, identical twins are expected to develop the disease at a rate of less than 50%. Sisters seem to have a higher risk of developing the disease than brothers -some studies put the risk to sisters at around 10%. According to the Lupus Foundation, offspring of lupus patients run a 1 to 5% chance of developing the disease over a lifetime.
In considering the issue of family risk, it’s really important to keep a basic principle in mind: statistics inform but don’t predict. What happens in the overall population may have no relevance in an individual case. Little is understood about the causes of lupus, so no doctor or study can reliably predict what will happen to any one person. What researchers are hoping to find is an association between family members who get the disease; in that association may be found a way to limit risk factors and thus to minimalize the occurrence of disease within a genetically susceptible group.
The thing that is crucial about family studies is this: if links between family members point the way to causes, they may also point the way to a cure. Complicating the search, however, is the fact that more than 100 genes have been implicated in the expression of lupus. And these genetic links vary according to ethnic group and also according to the type of lupus involved (ex., kidney, CNS, etc.)
So far, the family studies have yielded some very significant clues about where exactly in the genetic code the trait for this disease exists. An important finding from one research effort is that it doesn’t matter which parent contributes the genetic code for lupus; the chance of developing the disease is the same whether that gene comes from mother or father. Two studies currently under way that are looking at family associations are the Lupus Sister Research Study at the Feinstein Institute in New York, and the Family Registry and Repository, in Oklahoma. The Feinstein Institute is no longer recruiting participants but it seems the Family Registry still is.
I think the bottom line for those of us who have lupus–at least for me–is that each of us is born with a genetic makeup over which we have no control. Knowing that we have a genetic predisposition to one disease or another certainly has implications for our family. However, this is not a sentence; it’s information. In the case of lupus, there are risk factors over which we do have control. Pesticide exposure and sunlight, for example, may pose dangers for family members and they should be informed about those dangers.
In a way, my family has an edge; all of them know that lupus is a possibility. If they are symptomatic, this is one of the things a doctor can suspect early in the process. This diagnostic heads up can lead to prompt treatment, if necessary, and prompt treatment, as we know, usually makes a difference in the prognosis.