In a new study from UCLA Health, researchers have discovered new genetic clues related to autism, with a particular focus on families having at least two children with the disorder. This largest-ever study of such families has revealed previously unidentified risk genes and even posited that language delay and dysfunction should be seen as a central element of autism spectrum disorder (ASD).
Until now, most genetic studies concerning autism have concentrated on families with only one child affected by this neurodevelopmental disorder. This approach often overlooked families with multiple affected children, thus neglecting the investigation of rare inherited variations and their interaction with multiple common genetic variations. These contribute to the risk of developing autism.
Dr. Daniel Geschwind, the lead author of the study and a Distinguished Professor of Human Genetics, Neurology, and Psychiatry at UCLA, emphasized that the design of this study was crucial, and it aimed to address the lack of attention given to families with more than one child affected by autism.
Autism's genetic roots are profound, with an estimated 50% of the risk predicted by common genetic variations and another 15-20% linked to spontaneous mutations or predictable inheritance patterns. The remaining genetic risk is still a subject of ongoing investigation.
The study involved whole genome sequencing in 4,551 individuals from 1,004 families, including 1,836 children with autism. It revealed seven potential genes (PLEKHA8, PRR25, FBXL13, VPS54, SLFN5, SNCAIP, and TGM1) that are suspected to elevate the risk of autism. What's remarkable is that this discovery came from a much smaller cohort compared to similar studies, thanks to the examination of rare inherited DNA variations.
The study also explored polygenic risk, where a blend of common genetic variations can augment the chance of autism. This finding helps explain why parents carrying a single rare mutation might not exhibit signs of autism, even though their children might. It further reinforces the liability threshold model, a theory that suggests an accumulative effect of genes on the likelihood of developing specific traits.
One crucial discovery was the relationship between genetic risk for autism and language delay in children. Those with language delay were more likely to inherit a polygenic score associated with autism, a pattern not found with other traits like schizophrenia or bipolar disorder. This finding challenges the Diagnostic and Statistical Manual of Mental Disorders, 5th Edition (DSM-5), which doesn't regard language delay as a fundamental symptom of autism due to the variance in language ability among people with the disorder.
Dr. Geschwind stated, "This association of general risk for ASD that was strongest in those with language delay suggests that language is actually a core component of ASD." He called for this insight to be replicated in larger cohorts to strengthen its validity.
This pioneering research marks a significant step in understanding the intricate genetic mechanisms underlying autism, particularly in families with multiple affected children. By shedding new light on rare inherited variations and their role in ASD, the study could pave the way for more targeted diagnostic criteria and therapeutic interventions in the future.
Until now, most genetic studies concerning autism have concentrated on families with only one child affected by this neurodevelopmental disorder. This approach often overlooked families with multiple affected children, thus neglecting the investigation of rare inherited variations and their interaction with multiple common genetic variations. These contribute to the risk of developing autism.
Dr. Daniel Geschwind, the lead author of the study and a Distinguished Professor of Human Genetics, Neurology, and Psychiatry at UCLA, emphasized that the design of this study was crucial, and it aimed to address the lack of attention given to families with more than one child affected by autism.
Autism's genetic roots are profound, with an estimated 50% of the risk predicted by common genetic variations and another 15-20% linked to spontaneous mutations or predictable inheritance patterns. The remaining genetic risk is still a subject of ongoing investigation.
The study involved whole genome sequencing in 4,551 individuals from 1,004 families, including 1,836 children with autism. It revealed seven potential genes (PLEKHA8, PRR25, FBXL13, VPS54, SLFN5, SNCAIP, and TGM1) that are suspected to elevate the risk of autism. What's remarkable is that this discovery came from a much smaller cohort compared to similar studies, thanks to the examination of rare inherited DNA variations.
The study also explored polygenic risk, where a blend of common genetic variations can augment the chance of autism. This finding helps explain why parents carrying a single rare mutation might not exhibit signs of autism, even though their children might. It further reinforces the liability threshold model, a theory that suggests an accumulative effect of genes on the likelihood of developing specific traits.
One crucial discovery was the relationship between genetic risk for autism and language delay in children. Those with language delay were more likely to inherit a polygenic score associated with autism, a pattern not found with other traits like schizophrenia or bipolar disorder. This finding challenges the Diagnostic and Statistical Manual of Mental Disorders, 5th Edition (DSM-5), which doesn't regard language delay as a fundamental symptom of autism due to the variance in language ability among people with the disorder.
Dr. Geschwind stated, "This association of general risk for ASD that was strongest in those with language delay suggests that language is actually a core component of ASD." He called for this insight to be replicated in larger cohorts to strengthen its validity.
This pioneering research marks a significant step in understanding the intricate genetic mechanisms underlying autism, particularly in families with multiple affected children. By shedding new light on rare inherited variations and their role in ASD, the study could pave the way for more targeted diagnostic criteria and therapeutic interventions in the future.