Monthly Archives: June 2010

Schizophrenia brain signs in babies?

A long, long time ago,  in a galaxy just like ours….  

Let’s let’s try that again.

Some of you might recall a time when a popular idea regarding mental illness was that the fault, dear reader, was not in our genes  but in the way we communicated with each other.

In the  mid-1950s, a number of social scientists and psychotherapists developed proposals that attributed schizophrenia to the exposure to, and participation in, dysfunctional communication patterns in the family.

Some of the concepts flying around like drunken pelicans included  “double-bind communication,”  “pseudomutuality, and “pseudohostility.” (For a nifty overview, circa 1997, see this article.)

It was an intriguing idea that sort of jelled with a lot of us Homo saps who viewed mental illness as w-a-a-a-y more environmentally than genetically determined.  And even into the early 1960s, the majority of undergrad psych students would feel compelled to agree.

Today, in the nature versus nurture game, we  tend to be interactionists in our view of schizophrenia. We know it to be a debilitating mental disorder affecting one in 100 people worldwide, that most cases aren’t detected until a person starts experiencing symptoms like delusions and hallucinations as a teenager or adult. And by that time, the disease has often progressed so far that it can be difficult to treat. 

Infant’s brain image on left shows the larger lateral ventricles and a generally larger brain overall. Image provided by John Gilmore, MD.

 Now new research published online in the American Journal of Psychiatry offers the first evidence that early neonatal brain development may be abnormal in males at genetic risk fo schizophrenia.

 The scientists used ultrasound and MRI to examine brain development in 26 babies born to mothers with schizophrenia.  (Having a first-degree relative with the disease raises a person’s risk of schizophrenia to one in 10.)

 Among boys, the high-risk babies had larger brains and larger lateral ventricles—fluid-filled spaces in the brain—than babies of mothers with no psychiatric illness. The new findings were detectable in babies only a few weeks old.

“It allows us to start thinking about how we can identify kids at risk for schizophrenia very early and whether there things that we can do very early on to lessen the risk,” says lead study author John H. Gilmore, MD, professor of psychiatry and director of the  UNC Schizophrenia Research Center.

“Could it be that enlargement is an early marker of a brain that’s going to be different?” Gilmore speculates.

No difference was found in brain size among girls in the study. This fits the overall pattern of schizophrenia, which is more common, and often more severe, in males.

The findings, o course,  do not necessarily mean the boys with larger brains will develop schizophrenia. Relatives of people with schizophrenia sometimes have subtle brain abnormalities but exhibit few or no symptoms.

 “This is just the very beginning,” said Gilmore. “We’re following these children through childhood.”

 The team will continue to measure the children’s brains and will also track their language skills, motor skills and memory development. They will also continue to recruit women to the study to increase the sample size.

Les Lang

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Autism genetics: an emerging consensus

A large international consortium of researchers, including scientists at the University of North Carolina at Chapel Hill, have announced new discoveries that could help clarify the genetics of autism.

Their findings published online June 9th in Nature,  support an emerging consensus among scientists that autism is caused by many “rare variants” or genetic changes found in less than one percent of the population.

While each of these variants may only account for a small fraction of autism cases, collectively they appear to account for a greater percentage of individuals within the autism community. They are also providing into possible mechanisms involved in the disease.

The Autism Genome Project (www.autismgenome.org) collected genotyping data from 1,000 individuals with autism spectrum disorder, or ASD, and 1,300 without ASD. They found that people with the disorder tend to carry submicroscopic insertions and deletions called copy number variants, or CNVs, in their genome. Some of these variants appear to be inherited, while others are considered new because they are found only in affected offspring and not their parents.

These CNV in individuals with ASD tend to disrupt genes previously reported to be associated with autism or intellectual disabilities.

The study also identified new genetic risk factors for autism (genes known scientifically as SHANK2, SYNGAP1, DLGAP2 and the X-linked DDX53–PTCHD1 locus.)

Some of these genes belong to nerve synapse-related pathways, while others are involved in cell proliferation, cellular movement, and intracellular signaling – functional targets that may lead to the development of new treatment approaches.

“These findings provide further evidence that autistic behavior is the result of many rare, small genetic changes,” said Joseph Piven, MD, study co-author and a lead AGP consortium investigator. Piven is also Sarah Graham Kenan Professor of Psychiatry at UNC and director of the Carolina Institute for Developmental Disabilities. 

“While genetic abnormality or relevant CNV identified appears to account for only a handful of affected individuals, taken together these various CNVs in different locations throughout the genome are beginning to account for a significant number of occurrences of autism in the population. Identifying the genes and biological pathways associated with these genes will eventually lead us to new treatments for autism based an understanding of the underlying biological causes.”

Geraldine Dawson, PhD, research professor of psychiatry at UNC, also coauthored the new study.

The AGP consists of 120 scientists from more than 60 institutions representing 11 countries who formed this first-of-its-kind autism genetics consortium.  Since 2002, group members have shared their samples, data, and expertise to facilitate the identification of autism susceptibility genes.

Les Lang

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