have suggested that alterations in the mitochondrial DNA that were determined
by human migrations may be associated with the risk of suffering from autism.
- Mitochondria are
the powerhouses of the cells, generating energy for various cellular
- Scientists have
suggested a possible link between variations in mitochondrial DNA and
- The theory could
change the approach to the development of treatments for autism
research was published in JAMA Psychiatry
Mitochondria are tiny
organelles that are present in every cell of our body. They are known as the
power houses of the body. They generate energy from the nutrition that is
supplied to the cells by the blood, which is utilized for the functioning of
the body. Mitochondria also play a role in several other functions which
include the synthesis of the genetic material DNA and RNA, hemoglobin, estrogen
and testosterone, and the breaking down of cholesterol and detoxification.
‘Genetic variations in mitochondrial DNA due to ancient migrations could influence the development of autism spectrum disorders.’
Though most of the
cellular DNA is located within the nucleus, mitochondria have their own DNA,
which is solely inherited from the mother. Depending on the mutations that
took place over time, the mitochondrial group of genes have been classified
into haplogroups. Haplogroups consist of a group of genes that are inherited
together from a single parent and reflect the line of descent. Depending on the
human migration, different haplogroups moved to different parts of the world.
The mitochondrial haplogroups thus reflect the ancient migration patterns out
of Africa into the rest of the world.
scientists suggest that the genetic variations in the mitochondria may play a
role in the development of autism spectrum disorders (ASD). Autism spectrum disorders
a group of development disorders in which the patients suffer from difficulty
with communication and social interaction along with repetitive or restrictive
behavior. Patients have focused but long-lasting interests in certain topics.
They have a problem with conversations but can talk at length on their topic of
interest. They get upset if their routines or settings are suddenly changed.
They, however, usually have above average intelligence and may even excel in
the fields of mathematics, art, music and science. Genetic and environmental
factors have been implicated in increasing the risk of suffering from ASD. Medications
may be used to control symptoms of irritability, aggression, anxiety,
depression, hyperactivity and attention problems to some extent.
The scientists obtained
the genetic data for their study from the Autism Genetic Resource Exchange
(AGRE). The study was conducted on the data obtained from 1,624 patients and
2,417 healthy parents and siblings from 933 families.
scientists found that Europeans with the haplogroups I, J, K, X, T and U had a
higher risk of ASD as compared to those with HHV, which is the most common
European haplogroup. The risk was also higher in those with the Asian and
Native American haplogroups A and M
The increased risk for
ASD has a possible explanation. The variations in the mitochondria can affect
the brain and cause an imbalance between the excitation and inhibition of brain
activity thereby predisposing to ASD.
ASD is more common in
males as compared to females, similar to other mitochondrial diseases like
Leber hereditary optic neuropathy (LHON). This fact also increases the
possibility of it being linked to a mitochondrial disorder.
Taking the findings of
the study further, the scientists suggest that metabolic treatments could be
developed and evaluated in the future for their possible benefits in this group
- Autism Spectrum Disorder - (https:www.nimh.nih.gov/health/topics/autism-spectrum-disorders-asd/index.shtml)
- "Association between Mitochondrial DNA Haplogroup Variation and Autism Spectrum Disorders," JAMA Psychiatry, online Aug. 23, (2017). http://doi.org/10.1001/jamapsychiatry.2017.2604