This year saw the debut of increasingly complex techniques for growing and analyzing brain organoids and other tissue cultures in 3D.
Human cortical organoids, for example, can form functional connections in the brains of newborn rats and influence the animals’ behavior and sensations, a team reported in October, setting the stage to study faulty circuitry. Organoids grown from delicate individual neural rosettes can capture the complexities of neural tube development, according to work published in December. A technique for sequencing gene expression within organoids, described last July, makes it possible to determine what types of cells are affected by autism-related genetic variants, and how. And organoids with mutations in autism-related genes may also serve as useful drug screensthe scientists announced at Neuroscience 2022 in November.
Assembloids, clusters of organoids that model how two areas of the brain grow in tandem, can replicate connectivity differences seen in people with 22q13.3 deletion syndrome and mouse models of the condition, another team announced in Neuroscience 2022. And applying the CRISPR gene-editing tool to the assembloids may reveal which autism-related genes help direct the development and migration of interneuronsreported a November preprint.
Beyond organoids and brain assembloids, culturing multiple mouse stem cell lines together in a single dish can even lead to “embryoidsthe researchers announced in October. These models contain structures that mimic the heart and central nervous system, and may pave the way for investigating prenatal development in laboratory-grown human embryos.
Working together – common and rare variants:
At least six large-scale genetic studies this year have revealed how common and rare variants jointly influence autism onset and heterogeneity.
These variants work cumulatively in some cases to increase a person’s likelihood of having autism, although they may contribute differently to traits of the condition, the studies showed. For example, autistic people with a high number of common variants linked to the condition tend to have few co-occurring developmental disabilities, according to a June study, and people who carry rare de novo mutations tend to have fewer common variants, according to another published at the same time. But autistic children with language delays inherit more common variants than autistic children with typical language development, according to unpublished work presented in the 2022 American Society for Human Genetics conference in October.
Rather than working additively, common variants and a rare autism-related deletion within the 16p chromosome region have similar effects on the expression of other genes in the region, an October study to study showed, suggesting that the cumulative effects of many common variants can sometimes equal those of one rare variant.
Two additional studies published in August expanded the list of genes associated with autism and other developmental conditions and shed light on the role of inherited rare variants.
Getting to the mechanism behind the sex bias of autism:
The sex bias of autism is one of the condition’s biggest mysteries: Why, researchers continue to wonder, are boys and men nearly four times more likely to be diagnosed with autism than girls and women?
There is likely a combination of factors at play, but biological differences are central to the discrepancy, the 2022 findings suggest. For example, the x chromosome they may harbor mutations that increase a person’s likelihood of autism and have a huge effect on children, an October study found. Compared to boys, girls are also less affected by common inherited variants related to autism, another study reported in June. And in the womb, boys, unlike girls, tend to have behavior patterns. cortical gene expression that align with what is seen in the brains of autistic adults, according to work presented at Neuroscience 2022 in November.
It’s not all biology, though, according to a June study that attributes the sex bias of autism primarily to How is it diagnosed. That team found an equal ratio of autistic girls and boys when they corrected for differences in how boys and girls tend to perform on certain tasks during different periods of development.
New translation efforts:
Despite our advances in understanding the biology of autism, few efforts to translate those findings into treatments have been successful. Some industry players took steps to change that in 2022.
Some companies are taking up what has long been a challenge for the field: designing treatments for idiopathic autism that are not frustrated by the heterogeneity of the condition. based in switzerland Stalicla he hopes to get around that hurdle by using biological measures to define subgroups of autistic people and then designing specific treatments for each. Spectrum reported in June. Iama Therapeuticsan Italian start-up Spectrum profiled in October, instead goes for a single treatment with a known mechanism and then tries to identify the population of autistic children who would respond best to it.
Therapies designed for people with rare genetic conditions linked to autism largely avoid the problem of heterogeneity and have also made leaps and bounds by 2022. Multiple clinical trials for drugs that increase the expression of a key gene linked to Angelman syndromefor example, are In the works. And a treatment for Dravet syndrome, a genetic condition that can cause fatal epilepsy, reduced seizures in children with the syndrome in a clinical trial this year. Strong relationships between researchers and family groups they often encourage these tests; in some cases, researchers are studying their rare condition of own sonWhat Spectrum reported in a profile in July.
In December 2021, a committee organized by the lancet formally recommended a term for autistic people who require 24-hour life support: profound autism. The hashtag sparked a conversation that captured the attention of the advocacy and investigative communities throughout 2022.
The committee was intended to “draw attention to the fact that these children and adults exist, and that they need different services,” said co-chair Catherine Lord. Spectrum. Many welcomed the approach, including the Autism Science Foundation, which launched $35,000 in new grants to study profound autism, but others saw it as potentially isolate some autistic people of the larger community.
In February, a open letter with more than two dozen signatures called the term “highly problematic.” A November editorial on Spectrum by Autism Science Foundation President Alison Singer, arguing for of the term, he got as much support and resistance. Many in favor see the label as an opportunity to include more autistic people with high support needs in research. But their creation is not in keeping with the neurodiversity paradigm, eluding the experience of autistic people, the developmental psychologist argued. Sue Fletcher Watson in an answer to the editorial
Cite this article: https://doi.org/10.53053/JWJR9206