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In the first half of 2008 a team led by prominent CFS/ME researcher Dr. Jonathan
Kerr, published the results of a genetic study which identified 7 different subtypes
of the condition.
The study involved 55 CFS/ME patients from both the US and UK along
with 75 healthy controls. Blood samples were taken from all participants and genetic
analyses carried out. Genomic analysis revealed some common (neurological,
cancer, immunological, inflammatory, haematological) and some distinct (metabolic,
endocrine, dermatological, cardiovascular, connective tissue) disease associations among
the subtypes.
The results of which, along with information about symptoms
provided by patients, led to the discovery of the following subtypes of CFS/ME:
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Type 1 - high levels of cognitive problems, depression and anxiety as well as poor
sleep and high degrees of musculoskeletal pain.
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Type 2 - severe post-exertional fatigue, joint and muscle pains, anxiety and
depression.
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Type 3 - mildest form of the disease.
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Type 4 - moderate levels of body pain, cognitive impairment and sleep problems.
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Type 5 - most severe muscle weakness and predominance of gastrointestinal
problems.
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Type 6 - associated with significant postexertional fatigue.
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Type 7 - most severe form with high levels of musculoskeletal pain, swollen
glands, gastrointestinal problems, neurocognitive problems, anxiety, depression 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.
CFS/ME 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 CFS/ME 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 CFS/ME and
is dedicated to developing a diagnostic test and effective treatments for the condition.
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