Finding hints at new treatments for the disorder that causes verbal and motor tics,,
WEDNESDAY, May 5 (HealthDay News) -- A family in which the father and all eight of his children have Tourette syndrome held clues to treating the neurological disorder that can cause debilitating, involuntary motor and verbal tics.
By studying the family's genome, researchers identified a mutation on the HDC gene that encodes the enzyme L-histidine decarboxylase, which is involved in regulating levels of the neurotransmitter histamine in the central nervous system.
While the variant itself is likely very rare -- meaning most people with Tourette syndrome don't have the precise mutation -- what's known about the gene's function in the body hints at new treatments, researchers explained.
Previous research in mice has shown that manipulating brain levels of histamine by decreasing activity of HDC makes mice more likely to have repetitive behaviors, such as biting, rearing and chewing. "Those are behaviors that on face value look like human tics," said senior study author Dr. Matthew State, an associate professor of child psychiatry, psychiatry and genetics at Yale University School of Medicine.
Drugs that increase the release of histamine in the brain, but don't affect histamine levels in other parts of the body, are in the latter stages of development. Previous research has also shown that when given to mice, the drugs decrease the repetitive behaviors.
It's possible those drugs could also help people with Tourette syndrome, State said.
"In this case, genetics may point to the function of the gene, which points to what kind of mechanisms might be involved in the disorder," State said. "The idea you could go from a rare genetic finding to a new approach to treatment is something that doesn't happen very often."
The study is published in the May 5 online edition of the New England Journal
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