Autism Linked to Cellular Irregularity, Altered Energy Metabolism


Both genetic and environmental factors appear to play a role in the development of autism. Researchers are looking more closely at factors inside cells to learn more about the condition and have discovered that impaired mitochondrial dysfunction appears to play a role, at least in a subset of autistic patients.

Mitochondrial Dysfunction Can Lead to Developmental Delays

In a very small study, researchers from the University of California, Davis took blood samples from 20 children, half of which had full-syndrome autism and half who were developing normally. They found that the children with autism were more likely to have markers consistent with impaired mitochondrial function, mitochondrial DNA abnormalities and abnormalities in the levels of various enzymes produced by the mitochondria.

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Mitochondria, located in the cytoplasm outside the nucleus of the cell, are critical for converting nutrients into energy, especially important in the brain. Each mitochondrion has a chromosome composed of DNA. Mitochondrial dysfunction can occur from birth or later in life and may include a wide range of symptoms including developmental delays, heart problems, gastrointestinal disorders, and muscle weakness.

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Earlier studies that used muscle biopsies instead of blood samples indicate that mitochondrial disease may be 550 to 770 times higher in autistic children than in the general population. Impaired mitochondrial function has also been implicated in other neurological conditions, including Parkinson’s disease and Alzheimer’s disease.

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Lifestyle interventions including diet and exercise could potentially have an impact on autistic symptoms, hopes Geraldine Dawson, chief science officer of Autism Speaks.

“Certainly these findings need to be confirmed in larger studies,” said lead researcher Cecilia Giulivi PhD. It isn’t clear if the mitochondrial dysfunction causes autism or if it is a consequence of the developmental disorder. The study also did not include children on the less severe end of the autism spectrum.

She hopes the research could also potentially lead to blood tests used to screen infants even before behavior symptoms are evident.

The study is published in the Dec. 1 issue of The Journal of the American Medical Association.