Genetic Susceptability

[MomWithOCDSon]

Someone had posted a topic earlier this week about familial history of OCD and/or TS and whether or not that has a link to a current generation of PANDAS kids.

 

Then, in another link, there's been a discussion of a new therapy (TSO) for both autism and PANDAS. That autism/TSO web link led to yet another link that, while perhaps it's been posted here before, I don't recall ever having seen.

 

I knew they'd found an "OCD gene" in dogs; I didn't know they'd found one in mice, as well. But, more than related to OCD, it's related to the immune system, so there's yet another link between immune function (or dysfunction) and OCD:

 

"But animals with a defective version of the gene Hoxb8 groom themselves so much that they tear out patches of fur and develop skin sores. The behavior resembles a type of obsessive-compulsive disorder called trichotillomania, in which people tug out their own hair.

 

The Hox family of genes is best known for helping to organize the embryo’s body, but Hoxb8 has several effects. The protein encoded by the gene functions in neural development, so mice lacking it have abnormal spinal cords and sensory ability, including pain sensitivity. This defect could in theory provoke the rodents to wash excessively, although molecular geneticist Mario Capecchi of the University of Utah School of Medicine in Salt Lake City and colleagues note that Hoxb8-lacking mice also obsessively groom other mice. That suggests that overcleaning is not a sensory problem but a behavioral one originating in the brain.

 

When Capecchi and colleagues began looking for the Hoxb8-making cells in the mouse brain, they expected to find that the source was neurons that control grooming. To their surprise, the only cells producing Hoxb8 were microglia, immune cells that guard against pathogens. Although some microglia start out in the brain, others are born in the bone marrow and move in. Overall, adult mice with faulty Hoxb8 harbored about 15% fewer microglia in the brain than normal."

 

Science Now Article - Immune Gene and OCD

 

Thanks for the previous posts that led to this one!