The patient is a 52-year-old woman who was diagnosed with myalgic ME/CFS at the age of 25 after an infection with parvovirus B19 and has not been the same since. For the past twenty-one years, she has suffered from chronic fatigue, exercise intolerance, and post-exertional malaise and has been mostly housebound and often bedbound (up to 22 h per day).
The patient presented is interesting in several respects. Firstly, the m.8753_16566del variant has not previously been described as a cause of MID [mitochondrial disorder]. Second, the mtDNA deletion caused isolated complex-V dysfunction. Third, the mtDNA deletion manifested phenotypically despite a heteroplasmy rate of <10 % in muscle. Fourth, MID remained undetected for 21-years. Fifth, the mtDNA deletion manifested only in skeletal muscle. Sixth, the mtDNA variant first became symptomatic after a parvovirus infection. An isolated complex-V insufficiency was previously described at least in lymphocytes of ME/CFS patients. [5]
A muscle biopsy at the age of 39 years revealed an increased lipid content and a predominance of type II muscle fibers, which was considered a non-specific finding.
VO2 max tests showed a drastic reduction in aerobic capacity.
mtDNA analysis from muscle at 46 years of age revealed the m.8753_16,566 deletion with <10 % heteroplasmy. The deletion was larger than in patients with KSS but encompassed the entire ATP6 gene associated with complex-V of the respiratory chain. An abnormal complex-V band was detected in the MitoFIND assay, indicating that the mutation was a germline mtDNA deletion
intravenous immunoglobulins had a transient positive effect.
the mtDNA deletion caused isolated complex-V dysfunction […] manifested phenotypically despite a heteroplasmy rate of <10 % in muscle […] manifested only in skeletal muscle […] first became symptomatic after a parvovirus infection.
I hope we don’t get to a point where anyone with ‘biological’ changes don’t have ME/CFS.Interesting to see how this is framed as a "misinterpretation" or "mimicking" of ME/CFS, when very clearly the patient has ME/CFS (qualifying under the usual syndromic definitions, as quoted by Forestglip above). Why not simply speculate that this could be a potential cause for ME/CFS?
How easy is it to study mitochondria, and how much do we know about them? I’m assuming their functionality is highly dependent on the environment they are in - so isolating them might produce different behaviours?The only problem I have with a mitochondrial centric view of me/cfs is that I'd have guessed we would have found the problem by now if it was indeed usually in the mitochondria.
True, ME could involve a mitochondrial problem in only a few specialized brain cells. Very hard to find that unless you know what to look for (and where). Moreover, it might not show up in autopsy samples, or even living cells without the environmental factors that lead to ME.I’m assuming their functionality is highly dependent on the environment they are in - so isolating them might produce different behaviours?
How easy is it to study mitochondria, and how much do we know about them? I’m assuming their functionality is highly dependent on the environment they are in - so isolating them might produce different behaviours?
This is an important point that needs to be debated. I've heard that conditions like IH, CCI or even unidentified bone-infection can mimic ME/CFS. The problem is that those are treatable conditions. I've even met someone who suffered from hemochromatosis (?) or something and cried river saying that his life was now over because he had ME/CFS, and then got cured 3 years later after getting treated properly. I don't know the mitochondrial condition in this paper is treatable or not, but it apparently explains the symptoms. And the syndrome definition requires that the symptoms are not explained by other conditions.Interesting to see how this is framed as a "misinterpretation" or "mimicking" of ME/CFS, when very clearly the patient has ME/CFS (qualifying under the usual syndromic definitions, as quoted by Forestglip above). Why not simply speculate that this could be a potential cause for ME/CFS?