M.E. in families

Published in InterAction 39, Winter 2001

We regret that our medical adviser cannot respond to individual enquiries

Dear Doctor: M.E. in families

M.E. in families I have M.E. and so does my daughter. Is there any research to indicate why some families have more than one member affected? I m worried that there could be a genetic predisposition to getting this illness.

Professor Tony Pinching commented:

There is anecdotal and some limited formal evidence that the condition is more common in families. This is not surprising since CFS/M.E. is often triggered by infection, and there is a genetic influence in how we respond to and are affected by most infections. So people may be genetically predisposed to getting a fatigue state after certain infections.

Another possibility is that several members of the same family or household have been exposed to some common environmental factor (infection, or other trigger) that can provoke fatigue, or that can make it more likely to occur after some trigger. The most common triggers are common-or-garden infections that most people handle normally as short acute illnesses.

It is likely that more than one factor applies for the observation that CFS/M.E. is a bit commoner in families. The fact that there seem to be cluster outbreaks of this illness seems to argue against genetics as being the sole factor.

Recent research done in the USA indicates that identical twins are more likely to be concordant (i.e. both have the illness), which provides some formal support for the role of genetic factors. However, CFS/M.E. is not a genetically inherited disease, in the sense that muscular dystrophy or haemophilia are. But, just like heart or autoimmune disease, genetic tendencies can make an individual more susceptible to the effects of other factors.

The risk for M.E. is still low among those whose close relatives are affected. A family member of a sufferer should perhaps be especially careful to avoid working through or pushing themselves back to work prematurely after any infections; a period of convalescence to allow recovery might lower the risk of developing a fatigue syndrome.

Dr Sarah Myhill added

I often sees two or more members of one family similarly affected with M.E. This is hardly surprising. All diseases are caused by a combination of genetic and environmental factors, while linked conditions like thyroid disease, micro-nutrient deficiencies and allergies often run in families. Furthermore, families live together in the same environment, eating a similar diet and exposed to similar toxins and infectious agents.

I tend to find what works for one family member also works for others. I have had several cases where one member is used as a guinea pig to do the elimination dieting, for instance, and the others latch on to whatever worked. A knock-on benefit for other family members is that they tend to adopt the healthier lifestyle and the sleep and supplement regime of the M.E. patient, thus improving their health too.

Dr Kelly Morris explained

There is little research on M.E. running in families, as opposed to milder fatigue states. However, in addition to the factors outlined above, family attitudes and coping strategies are suggested to play a part in some cases, for example, some children may adopt a don't let illness stop you working attitude from their parents.

However, given that fibromyalgia and chronic pain can also be familial, some researchers have raised the question of possible genetic defects in pain pathways. Rarely a family will have a specific genetic defect, as in the case of one family with many members affected by CFS who shared a defect in the activity of their natural killer immune cells.