Background:

Dravet’s syndrome, a childhood disorder characterized by the onset of seizures within the first year of life, has symptoms common with Autism Spectrum Disorder (ASD) including—but not limited to—hyperactivity, stereotyped behaviors, inhibited social interactions, and marked cognitive deficits. Children with Dravet’s syndrome have a mutation in a string of DNA called the SCN1A gene. While most people have two copies of SCN1A, children with Dravet’s syndrome have only one functioning copy of the gene.

What’s New:

In the 22 August 2012 online edition of the journal Nature, researchers report that genetically engineered mice lacking one copy of SCN1A exhibit hyperactivity, anxiety, increased stereotyped behaviors, deficits in social interactions, and impaired cognitive function. According to the report, a specific type of neuron, called a GABAergic interneuron, requires two copies of SCN1A to hold back the transmission of electrical stimulation. When the researchers give the mice clonazepam, a type of drug known to help neurons block the spread of electric activity, the mice no longer exhibit impaired social behaviors and cognitive deficits.

Why it’s important:

Experiments with the mouse model of Dravet’s syndrome show that disruption of neuron inhibition may be one of the underlying causes of autism. Drugs that can restore the balance between inhibition and excitation of neurons are a potential therapeutic strategy for treating symptoms in some ASD-related syndromes.

How Do Autism Risk Genes Affect Brain Function?

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