Anorexia May Be Genetic, Not Just a Mental Health Issue

For the first time, scientists have located a genetic variant for anorexia nervosa – an eating disorder that until now was believed to be entirely psychiatric in nature. Genetic variation refers to the variation in the DNA sequence in the human genome. [1]

Researchers at King’s College London, the University of North Carolina, and Stanford University found that people with anorexia had a genetic variant on chromosome 12, but those without the disorder did not. This chromosome has been associated with type 1 diabetes and autoimmune disorders.

The finding could lead to new or repurposed treatments for anorexia. Currently, anorexia is treated with cognitive analytic therapy (CAT), cognitive behavior therapy (CBT), interpersonal therapy (IPT), focal psychodynamic therapy, and family therapy. [1] [2]

It also sadly means that anorexia patients could pass the disease to their children. [3]

Source: Office on Women’s Health

Prior to the study, anorexia nervosa was thought to be fueled by a combination of physical, social, and environmental triggers, including anxiety, depression, and the West’s obsession with thinness and outward appearance. [3]

Teasing Out the Genetic Connection

For the research, the scientists compared the genetic code of 3,495 individuals with anorexia to that of 10,982 healthy people. [2]

The team found faulty genes in over half of the anorexic patients they analyzed – genes that are associated with neuroticism, schizophrenia, and metabolism.

Professor Cynthia Bulik, of the University of North Carolina, said:

“Anorexia nervosa was significantly genetically correlated with neuroticism and schizophrenia, supporting the idea that anorexia is indeed a psychiatric illness.” [2]

However, Bulik added:

“We identified one genome-wide significant locus for anorexia nervosa on chromosome 12, in a region previously shown to be associated with type I diabetes and autoimmune disorders.

We also calculated genetic correlations — the extent to which various traits and disorders are caused by the same genes. Anorexia nervosa was significantly genetically correlated with neuroticism and schizophrenia, supporting the idea that anorexia is indeed a psychiatric illness.

But, unexpectedly, we also found strong genetic correlations with various metabolic features including body composition (BMI) and insulin-glucose metabolism. This finding encourages us to look more deeply at how metabolic factors increase the risk for anorexia nervosa.” [2]

The researchers are continuing to increase their sample sizes and view the outcome of the study as the beginning of genomic discovery in anorexia nervosa.

Sources:

[1] The Huffington Post

[2] Psych Central

[3] The Telegraph

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Could Boosting the Immune System Halt Autism and Schizophrenia?

Scientists have for years theorized that the immune system and the brain are more interconnected than previously thought, with findings of recent studies backing this hypothesis. For example, researchers recently discovered there is a physical connection between the immune system and the brain’s blood supply. Now, researchers have recently begun to find out that there may be a more psychological connection.

According to researchers at the University of Virginia (UVA) and the University of Massachusetts (UMass) Medical School, the immune system may directly affect social behavior in certain animals, such as mice. The finding could have enormous implications for people with autism-spectrum disorders or with schizophrenia. [1]

Jonathan Kipnis, professor of neuroscience at UVA in Charlottesville, said:

“The brain and the adaptive immune system were thought to be isolated from each other, and any immune activity in the brain was perceived as sign of a pathology. And now, not only are we showing that they are closely interacting, but some of our behavior traits might have evolved because of our immune response to pathogens.

“It’s crazy, but maybe we are just multicellular battlefields for two ancient forces: pathogens and the immune system. Part of our personality may actually be dictated by the immune system.”

Kipnis and his colleagues found that blocking one particular kind of immune molecule in a mouse’s brain caused abnormal behavior that vanished after restoration of the molecule. [2]

When this molecule, called interferon gamma, was genetically blocked, the rodents’ brains became hyperactive and specific areas of the brain that govern social interaction were unable to function properly. The affected mice – normally highly social creatures – interacted significantly less with the other mice.

The researchers say this means that the immune system, along with controlling whether or not we get sick, also appears to control our desire to interact with others.

And that, in turn, could mean that immune system problems might play a role in one’s inability to have normal social interactions. [2]

Read: Autistic Children Found to Have Fewer Healthy Gut Bacteria

Kipnis said:

“Whether we like it or not, there is a piling up of evidence that the immune system has a major impact on brain function: The brain is not isolated from the rest of the body.”

Fascinatingly, researchers say proof that immunity and social interaction are closely related lies in the fact that infections spread rapidly when animals are in close contact. The immune system-social interaction theory has been tested in mice, rats, flies, and fish using publicly available gene-expression data.

Fascinatingly, the researchers theorize that immunity and social interaction are closely related due to the fact that infections spread rapidly when animals are in close contact. Using publicly available gene-expression data, the immune system-social interaction theory has been tested in mice, rats, fish, and even flies.

When mice or rats are housed together, for example, there is an increase in the genes that interferon gamma activates, whereas those same genes are decreased in socially isolated rodents.

Zebrafish and flies exhibited a similar pattern.

Tony Filiano, a postdoctoral associate in Kipnis’ lab, said:

“Our hypothesis is that interferon gamma might have evolved as an efficient way to control the anti-pathogen response when organisms are social.”

If the immune system and social behavior evolved alongside each other, this could explain the results of other autism studies. Earlier this year, one such study showed that some pregnant women with elevated blood levels of interferon gamma went on to have children with autism and intellectual disability.

While interferon gamma is needed for social behavior, the study suggests that too much of the molecule might shut off its activity.

The findings might also explain why some children with autism seem to become more social when they have a fever, as elevated levels of molecules such as interferon gamma accompany fevers.

Kipnis says that understanding the link between the immune system and social behavior might help scientists find drugs that treat autism. Clinicians might be able to administer the medication in the cerebrospinal fluid, rather than via the brain. [3]

Sources:

[1] Gizmodo

[2] RT

[3] Scientific American


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