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Exploring Two Distinct Autism Subtypes Linked to Varying Brain Activity

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Brain Scans of Autism

New research indicates divergent brain connectivity in people with autism, showing both enhanced and diminished inter-brain region connections.

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Recent studies show that individuals diagnosed with autism may present either strong or weak neural connectivity patterns. These variations are linked to distinct mechanisms within the brain, hinting at the existence of multiple autism subtypes.

“We have identified major autism subtypes associated with differing biological mechanisms,” notes Alessandro Gozzi from the Italian Polytechnic University in Rovereto.

Autism, often viewed through the lens of neurodiversity, affects approximately 780 individuals per 100,000. Common traits include social interaction challenges, sensitivity to sensory stimuli, and restricted interests. However, the intensity and manifestation of these traits vary widely.

For years, neuroimaging techniques such as functional magnetic resonance imaging (fMRI) have been used to identify unique autism signatures in the brain. “No definitive single signature has yet been identified,” Gozzi states. Some researchers have observed hyperconnectivity in some brain regions, while others have noted low connectivity or a combination of both patterns.

Many previous studies overlooked autism’s diversity, according to Gozzi. To address this, his team studied 20 mouse models with mutations in genes linked to human autism. fMRI results showed variations in connectivity; eleven strains demonstrated primarily hypoconnectivity while nine showed hyperconnectivity.

“These conflicting connectivity signatures are indicative of different underlying mechanisms,” Gozzi explains. They mapped protein interactions associated with the mutated genes. Mice with lower connectivity showed interactions with synapse-related proteins, while hyperconnected mice interacted with proteins linked to gene regulation and immune function.

Furthermore, the research team analyzed fMRI data from 940 autism patients compared to 1,036 age-matched controls. Among the autistic participants, 24% exhibited hypoconnectivity and 17% hyperconnectivity. “At least two biologically distinct autism subtypes are evident,” Gozzi asserts.

Nevertheless, 59% of the autistic population does not fit into these classifications, potentially due to the specific genes selected for study. “Our findings do not suggest these are the only subtypes,” Gozzi clarifies. These were merely the ones detectable through their research methods.

Natalie Sauerwald, a researcher at New York’s Flatiron Institute, concurs that there may be additional, yet unidentified, subtypes of autism. She emphasizes that this work sheds light on autism’s heterogeneity and the biological factors involved.

Challenges persist in utilizing animal models for autism research. Humans have numerous genes, each with minimal individual effects on autism risk. Consequently, studied mice may not represent the full spectrum of autism, as noted by Sauerwald.

Some of the genes examined also relate to developmental delays. Thus, studies like this may only reflect individuals with autism who experience developmental deviations, rather than those without.

Looking ahead, connecting genetics, brain connectivity, and behavioral traits will be crucial to fully understanding autism’s diversity, according to Sauerwald.

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Source: www.newscientist.com

Children and teenagers experience varying symptoms from Long Corona

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The impact of the long corona pandemic appears to vary by age

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Symptoms of long COVID appear to be very different in young children and adolescents, and a better understanding of how the symptoms manifest could aid in diagnosis.

So far, most research on long-COVID has focused on adults, in part because of a “misconception that children can't get long-COVID,” he said. Rachel Gross At New York University.

Gross and his colleagues are currently following 751 children ages 6 to 11 and 3,109 children ages 12 to 17 whose parents say they had previously been infected with the SARS-CoV-2 virus.

The researchers defined long COVID as having at least one symptom that lasted more than a month, started or worsened during the COVID-19 pandemic, and was present at the time of the study.

Among young children, these symptoms primarily included sleep problems, difficulty concentrating, and abdominal problems such as pain, nausea, vomiting, and constipation.

The symptoms were uncommon among about 150 children of the same age who had not previously been infected, and were confirmed by the absence of antibodies against the virus in their blood samples.

In contrast, symptoms in the 1,300 uninfected young people typically included pain, fatigue and loss of smell or taste.

It's unclear why symptoms differ across different age groups, but Gross said it could be due to differences in hormones or immune systems, or that teenagers may simply be better able to vocalize their symptoms than younger kids. Danilo Buoncenzo A study from the Gemelli University Hospital in Rome, Italy. For example, a teenager may complain of fatigue, but a caregiver may only notice lingering symptoms in a younger child when they vomit.

Armed with this data, the researchers developed a score that ranks how likely a young person's symptoms are to have long-Covid. Currently, diagnosis depends on doctors ruling out other illnesses and recognizing that long-Covid can take many different forms. “Doctors would prefer a score or more objective criteria. Such a tool would definitely help clinicians at least recognize that a child may have long-Covid,” Buoncenso said.

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Source: www.newscientist.com