New Genetic Variant Linked to Severe Autism Identified
A newly discovered rare genetic variant linked to autism spectrum disorder (ASD) could shed light on the role of synaptic function and cognitive defects associated with the disorder. The research findings appear in the journal Nature.
Because females are less likely than males to receive an ASD diagnosis but tend to have more severe symptoms associated with the disorder (particularly in those with a close female relative who also has ASD), Aravinda Chakravarti, PhD, from Johns Hopkins University, and colleagues sought to examine potential genetic variants for ASD. The gene sequences of ASD patients from 13 families in which more than one female had received an ASD diagnosis were compared to the gene sequences of individuals from a public database.
Four potential culprit genes were identified in the ASD patients, with one (CTNND2) in the region of the genome known to be associated with cri-du-chat syndrome. After studying the gene's effects in zebrafish, mice, and cadaveric brains, the scientistis discovered that the protein produced by CTNND2 impacts the regulation of other genes as well. Mutations in CNNTD2 disrupted the synapses along brain cells, which is consistent with recent research suggesting that genetic mutations may be associated with autism are involved in synapse development.
While the CTNND2 variants with autism are extremely rare, the results of this work add to the growing evidence that abnormal synaptic function may be connected to the cognitive defects in ASD, Chakravarti adds. Next steps include assessing the functions of the three other genes with a potential link to ASD in autism-affected families.
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