Researchers working with mice discovered that a gene mutation linked to autism stunts the normal brain-cell branching needed to connect with other brain cells. They then restored the normal branching by administering a brain-cell growth factor – pointing the way to a potential treatment for at least one form of autism.
The Brown University scientists began by tracing the effects of a genetic mutation associated with at least one severe form of autism – Christianson syndrome. The defective gene fails to produce a protein called NHE6. NHE6 helps regulate the acidity inside neurons (brain nerve cells). This increased acidity degrades an important cell growth factor called BDNF and produces neurons that lack the branched structures that form normal brain-cell connections.
The researchers then restored normal neuron branching by administering BDNF directly to cells with the genetic defect.
"One of the overriding problems in disorders like autism, we think, is that it's a problem of communication between different areas of the brain and neurons communicating with each other in networks," explains psychiatrist Eric Morrow, the study’s senior author.
Though Christianson syndrome is a rare form of autism, deficient NHE6 has been associated with other forms of autism as well, Morrow adds. “In generalized autism, this protein is down regulated. That meant to us that [these results] are relevant to a sizeable subset of autism.”
Several existing medications are known to increase of mimic BDNF in the body. But much more research is needed to determine whether a BDNF-related medicine could safely and effectively treat Christianson syndrome or other forms of autism.
“While this study represents the earliest stages of treatment research, it embodies the kind of work needed to identify medicines that treat the pathology – not just the symptoms – underlying some forms of autism,” says Daniel Smith, Autism Speaks senior director for discovery neuroscience. “It’s an exciting advance in our knowledge of Christianson syndrome. But we need a long-term investment to test its translation from brain cells to humans.”
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