Mitochondrial Disorders and Autism

Mitochondria are minute organelles that serve to stabilize intracellular levels of calcium and play a prominent role in mediating a certain type of cell-death, the latter called apoptosis. However, the best known function of these organelles is their role as the so-called powerhouses of the cell. With the sole exception of red blood cells mitochondria are found in all cells of the body. Their role in energy production ties them to almost every cellular process imaginable. When mitochondria do not work properly the resultant lack of energy translates into observable symptoms. These symptoms include, among many others, slowed growth, muscle weakness, paralysis of eye movements, heart/liver disease, diabetes and neurological problems. In some affected females repeated mid- and late pregnancy abortions may be the presenting symptom. For unknown reasons mitochondrial disorders may target a particular organ or many of them. Disturbances in mitochondrial function have been related to a number of clinical conditions, some of which are associated to gene defects but many still of unknown origin.

mitochondria
The figure illustrates some of the organs usually affected by mitochondrial disorders.

Mitochondrial conditions and its relation to autism spectrum disorders (ASD) acquired a lot of attention after a young girl named Hannah Poling received compensation by the federal vaccine court. Hannah developed normally until she received a series of vaccines. Ever since she lost her vocabulary, eye contact and exhibited stereotypical behaviors all typical of autism. The CDC clarified the court’s ruling by specifying that vaccines in this case were not the cause of “autism”. Rather a preexisting condition (in this case mitochondrial disorder) provided for a generalized brain disorder (or encephalopathy) that had many manifestations including those of autism.

I must say that I know Jon and Terry Poling, the parents of Hannah. Jon did his Neurology residency at Johns Hopkins and some of his witnesses are close friends and esteemed colleagues. I do not believe that Jon necessarily blames the mercury in vaccines, nor denies the benefits of vaccines accrued throughout recorded medical history. However, he would argue that in certain children with known genetic or metabolic vulnerabilities revising the vaccination schedule would be a prudent alternative.

There are many metabolic disorders associated with autism-like symptoms, e.g., phenylketonuria (PKU), disorders of purine metabolism, biotinidase deficiency. Probably the most common of all of these are mitochondrial disorders. Studies suggest that the prevalence of mitochondrial disorder in ASD approximates 5%. Broadening the diagnostic criteria, and increasing inclusion of atypical cases, provides for a prevalence rate of about 40%. Diagnosis is based, in part, on morning fasting levels of different metabolites including lactic acid, pyruvic acid, acyl-carnitine, and ammonia. In some cases targeted gene testing or even a skin and muscle biopsy may be needed in order to establish a diagnosis. There are no known treatments for mitochondrial disorders. However, preventive measures such as avoiding dehydration and treating fevers may be of some benefit.

I have previously mentioned that the cerebral cortex is composed of modular units called minicolumns. These units act as the microprocessor of a computer. In autism, the cerebral cortex has many more minicolumns albeit developmentally malformed. Similar to mitochondrial disorders, the cerebral cortex of autistic individuals could malfunction when exposed to metabolic exigencies (see https://corticalchauvinism.wordpress.com/2013/01/29/what-causes-the-mayor-symptoms-of-autism-part-1/).

In summary, the main observation of this blog is that mitochondrial disorders were once considered a rare cause of autism but broadening of the criteria suggests a higher than expected prevalence. Although the threshold has to be low when ordering diagnostic tests for mitochondrial disorders, trying to predict who may or may not have a mitochondrial disorder is fraught with limitations. Many of the symptoms characteristic of mitochondrial disorders are common to autism: cognitive impairment, motor and behavioral disturbances, seizures. Furthermore, once you obtain a positive diagnosis, treatment options are limited. However, there is hope that in the near future new modes of therapy will make a difference in the quality of life of these patients. Results of clinical trials (http://www.sciencedirect.com/science/article/pii/S1096719211003787) testing new drugs have offered promising results.

[4/15/2013 Addendum: At a Think Tank in Maryland Dr. Richard Frye stated that autistic patients with mitochondrial disorders had a more prominent history of motor delays and a higher prevalence of seizures that idiopathic cases. Contrariwise, the prevalence of hypotonia (diminished muscle tone) tends to be lower in patients with mitochondrial conditions as compared to idiopathic autism. Dr. Robert Naviux added the importance of abstaining from using valproic acid (Depakote) in this patients population. Valproic acid is an anticonvulsant but its use has been associated with increased oxidative stress and mitochodrial dysfunction, see http://toxsci.oxfordjournals.org/content/86/2/436.abstract%5D

7 responses to “Mitochondrial Disorders and Autism

  1. Mitochondria dysfunction is a common theme is autism research. Meechan et al (2011) found that ‘Thereafter, functionally similar subsets of 22q11 genes–especially those that influence the cell cycle or mitochondrial function–remain expressed, particularly in the developing cerebral cortex, to regulate neurogenesis and synaptic development. When dosage of these genes is diminished, numbers, placement and connectivity of neurons and circuits essential for normal behavior may be disrupted. Such disruptions likely contribute to vulnerability for schizophrenia, autism, or attention deficit/hyperactivity disorder seen in most 22q11DS patients’.

    http://www.ncbi.nlm.nih.gov/pubmed/20833244

    The 22q11 deletion syndrome is not inherited, 93% of cases are caused by a de novo sperm or egg mutation, and 77% of cases have an imune deficiency including increased rates of auto-immune disease.

    http://www.ncbi.nlm.nih.gov/books/NBK1523/

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  2. It has been known for decades that a very small percentage of vaccine users could react very negatively to a vaccine. Human or animal, thus the vaccination compensation bureau was invented. With her unfortunate unknown pre existing condition, even if it was known, who would have know the effect? Now one of the risks maybe better known. Maybe other non vaccinated children with pre existing conditions are exposed to other triggers, like live viruses or some other toxin and end up with autism. Billions and billions of animal have been vaccinated over last 80 years, with no pandemic of neurological problems, Yet a very small percentage would react very badly. No one knew exactly why. Now this little unfortunate girl might help in unlocking those secrets. With 26 percent of the known human genome defective, there maybe other conditions that makes vaccines more risky. But this is a very small percentage. The rates of autism in the non vaccinated population and the vaccinated population are supposedly statistically the same. So what exactly is going on. Are all predisposed children doomed to autism? I know that identical twin studies show a 90 percent chance of shared morbidity with autism. But it is not 100 percent. So
    what complicated systems are involved? In some cases, do vaccines decrease the autism rate such that the two totals of vaccinated autistic children, nonreactive and reactive and the two totals of unvaccinated children, nonreactive and reactive, balance out. I don’t know, but I believe the answers are very complicated and cut across many disciplines of science and medicine. There will be no simple solution in understand autism. But don’t blame vaccines, children are producing their own antibodies all the time,which all vaccines just help do with really nasty bugs, as a preemptive measure. Medicine has never been 100 percent safe, and never will be.

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  3. I came back a few days ago,from seeing a fairly famous mito specialist,who believes I have a deficiency of more than one mitochondrial complex,and that my CFD is part of the whole picture.I am still waiting on test results,but this doctor was almost ready to diagnose me without them.What the mito specialist thinks,is that I have one of the many de novo mito deficiency syndromes that are found all the time now.I was just checking in here,to see what you had posted on mito.I love the illustration here,as I have severe involvement with everything here,and more.Never saw it before.My lack of muscle development is especially profound.

    To address the point the commenter above me has made,Like a lot of people diagnosed with mito,I have a number of other diagnoses.One of these is cerebral folate deficiency.Both mitochondrial disease,and CFD have a strong basis in epigenetics,as do schizophrenia and other diseases that are on the increase,but do not get the publicity autism does.I have found quite a bit of late that points to environmental toxins,drugs and other things that pregnant women have been exposed to that could very well have caused epigenetic damage that would account for the increase in autism,and other conditions.We are probably looking at cumulative generational exposures of at least 100 years or more.

    You might want to look at this blog
    http://prenatalexposures.blogspot.com/
    As well as this BBC documentary from December,2012

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  4. Thank you for the information you provided. You hit on all the more important points for mitochondrial disorders: how it affects multiple organs, link to cerebral folate deficiency, and epigenetics. I look forwards to watching the video. Thanks.

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