Gene associated with autism linked to itch response, study finds

Date:
July 29, 2021
Source:
North Carolina State University
Summary:
A gene associated with autism spectrum disorder (ASD) and pain
hypersensitivity may actually decrease itch response, according
to new research.



FULL STORY ==========================================================================
A pilot study from North Carolina State University has found that a gene associated with autism spectrum disorder (ASD) and pain hypersensitivity
may actually decrease itch response. Atopic dermatitis and pain hypersensitivity are both conditions associated with some types of ASD.


==========================================================================
The gene in question, contactin associated protein 2 (CNTNAP2),
is thought to be linked to a mutation associated with some forms of
autism. This gene is found throughout the dorsal root ganglia (DRG),
which are clusters of sensory cells located at the root of the spinal
nerves. The DRG is the superhighway that transmits sensations of both
pain and itch from the skin through the spinal cord to the brain.

"Since atopic dermatitis is often associated with ASD and CNTNAP2 is both linked to pain hypersensitivity in ASD and expressed in almost all DRG
sensory neurons, we wondered whether CNTNAP2 might also contribute to
itch behavior," says Santosh Mishra, assistant professor of neuroscience
at NC State and author of the study.

Mishra compared itch response in mice with the CNTNAP2 gene to those
without it. In the presence of both histamine and non-histamine based
stimuli, the CNTNAP2 knock-out mice, or mice without the gene, had a
reduced itch response compared to mice with the gene.

"If there is a link between ASD and atopic dermatitis, then mice without
a normal CNTNAP2 gene would be expected to have an increased itch response
just as they have increased sensitivity to pain," Mishra says. "There are several possible explanations for this finding, ranging from standard physiological differences between humans and animals to CNTNAP2's
potential role in releasing neuropeptides that could affect this response.

"But we also know that pain can suppress itch sensation and vice
versa. Just as some humans with ASD have higher pain sensitivity, so do
mice without CNTNAP2.

That pain sensitivity may be inhibiting the itch sensation." Mishra hopes
that this pilot study may pave the way to further exploration of the
role of CNTNAP2 in itch.

"The functional role of CNTNAP2 in the neural transmission of itch is
unknown," Mishra says. "While this study sheds light on the possible
linkage between ASD and itch, it's limited because it is primarily
based on behavioral, not cellular or molecular, results. Future studies
may be required to dissect the molecular underpinnings of CNTNAP2 and
itch sensation." The study appears in the Journal of Investigative
Dermatology and was supported by the National Institutes of Health and
NC State seed funding.

========================================================================== Story Source: Materials provided by
North_Carolina_State_University. Original written by Tracey Peake. Note: Content may be edited for style and length.


========================================================================== Journal Reference:
1. Santosh K. Mishra. The Role of CNTNAP2 in Itch Sensation. Journal of
Investigative Dermatology, 2021; DOI: 10.1016/j.jid.2021.07.152 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2021/07/210729122129.htm

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