Genetic study finds seven different types of Chronic Fatigue Syndrome

Geneticists have discovered the biological basis for seven different subtypes of chronic fatigue syndrome which correspond with different symptom patterns in patients.

For a long time it has been suggested that not all cases of chronic fatigue syndrome (CFS), also known as myalgic encephalomyelitis (ME), are exactly the same and that there are in fact several subtypes of the disease. This view has been based on research findings which have shown for example that some patients have specific immune system or hormonal abnormalities while others do not.

A new study carried out by researchers at St George's Hospital, University of London, now provides genetic evidence that there are indeed variations of the disease and that these influence the symptoms that predominant in individual patients.

The results of the study are due to be officially presented at a ME/CFS conference in Cambridge, England which is being organised by ME Research UK and the Irish ME Trust.

The study involved 55 ME/CFS patients from both the US and UK along with 75 healthy controls. The researchers took blood samples from all participants and carried out genetic analyses.

Seven Subtypes of ME/CFS

Results showed seven distinct genetic patterns amongst the patients which were linked to specific symptom patterns.

These are:

Type 1 - high levels of depression and anxiety as well as poor sleep and high degrees of pain.
Type 2 - severe post-exertional fatigue, joint and muscle pains.
Type 3 - mildest form of the disease.
Type 4 - moderate levels of body pain and sleep problems
Type 5 - most severe muscle weakness and predominance of gut problems
Type 6 - associated with significant fatigue
Type 7 - most severe form with high levels of pain, swollen glands and headaches.

It was found that types four and six were the most common forms of the condition.

Perhaps unsurprisingly it was found that most of the genetic markers in patients involved the regulation of the immune system. Strong evidence from other studies suggests that the immune systems of patients' remains activated after an initial trigger such as a viral infection. It is suggested that this itself is likely to cause symptoms and results in unbalanced defences which can allow other infectious agents such as bacteria and fungal organisms to cause various infections.

ME/CFS support organizations such as those organising the Cambridge conference are hoping that this information will lead to blood tests which will make diagnosis of the condition much easier and more accurate and will allow for tailoring of treatment based on the particular variant the patient is suffering from. Currently, diagnosis of ME/CFS is based purely on symptomology which is often difficult given that so many symptoms overlap with many other diseases.

Neil Abbot of ME Research UK said: "The discovery of a 'thumb-print' for the illness would be the single greatest advance that could be made because, at the moment, diagnosis is on the basis of a set of vague symptoms association with other illnesses.

"It's a hard illness to get a handle on, so a clinical test would be the single best way forward for everyone."

Lead researcher Dr. Jonathan Kerr said: "We must now determine what these sub-types represent, as they appear to be biologically meaningful, and discover their natural history and possibilities for treatment."

Dr. Kerr has been one of the most prominent researchers into the genetics of ME/CFS and is dedicated to developing a diagnostic test and effective treatments for the condition.

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written by paula gilfedder, May 09, 2008

I am over the moon that finally it looks like we are going to conquer this awful illness thanks to the brilliant Dr. Kerr and all the other wonderful researchers. I seem to fit into two or three of the catagories shown above but perhaps that can be sorted out when the time comes. At last there is hope for us all!!!

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written by Nin Horrox, May 26, 2008

Well done Dr Kerr for confirming the genetic link! I also fit into two or three of these above categories and after expert diagnosis in 2005, had a CFS bloodtest done by a brilliant bio chemist in London. The results showed that my CFS/Fibro symptoms were being caused by mitochondrial malfunction (not making enough ATP)and poor translocator protein function, with the possibility of it being due to a retention problem. At that stage I was a 'wheelchair' case with brainfog and severe muscle pain. However since taking Guaifenesin tablets to correct this retention issue, (www.fibromyalgiatreatment.com) I've recovered significantly, can walk again and am having more painfree days. I'd highly recommend this treatment to get better. By the way, Genetic research is also underway in the USA to confirm this possible cause (phosphate retention) of CFS/ME/Fibro.

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written by Mirabell, June 10, 2009

I don't fit into either category, and so I don't find it very useful. I am a mix between several of this. I am sceptical to dividing the subtypes according to symptoms, I would rather think a division based on findings (mitocondries etc) would be more usefull.

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written by Maff, June 10, 2009

A very good point Mirabell. The problem at present is there isn't enough coherent evidence of the various biological abnormalities in ME/CFS to be able to categorize patients that way....so doing it by symptoms is the next best thing. I'm sure in the future the subtypes can be refined based on both types of data and then we'll really be on our way to effective diagnosis and treatment.