Archives for the month of: November, 2009

The whimsical décor at the Baby Lab at the University of California, San Diego (UCSD), is designed to appeal to its most important visitors: the 400-plus babies and toddlers who have visited the cozy space since 2002.

Paintings of trees with spindly brown branches and plump green leaves cover the walls. Books, plastic cars and coloring books spill out across the carpeted floor and fill several plastic bins.

The children who come here are as young as 3 months on their first visit, and return every few months to participate in a battery of tests of their social behavior and perceptual processing — the brain’s response to non-social stimuli, such as looking at an ordinary object.

About one in four of these children is particularly interesting to the researchers: They are the younger siblings of children with autism, and are much more likely to develop the disorder than are those without a family history of it. Over the past few years, scientists have gathered heaps of behavioral data from these so-called ‘baby sibs’, but the Baby Lab is among the first to look for distinct signatures of brain activity.

The lab’s studies are ongoing, but two published reports have uncovered surprising differences between baby sibs and age-matched controls. Previous imaging work on face processing in people with autism had found abnormalities, suggesting to many researchers that their brains are slow to process social information. But the Baby Lab team is finding that during tests of sensory or perceptual processing, baby sibs show abnormally fast brain responses, rather than a delay.

Lead investigator Karen Dobkins says these data suggest an alternate interpretation of autism’s origins. Instead of resulting from a disruption of the brain’s social behavior circuits, she says, the disorder could arise from early upsets in perceptual processing, which eventually cause more noticeable social problems.

“We know that the hallmarks of autism are social in nature, but social systems develop later than sensory systems,” says Dobkins, professor of psychology at UCSD. “How on earth are you supposed to respond appropriately, behave appropriately, if you don’t perceive your world properly?”

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SFARI, November 2009.

Deletions or duplications of chromosomal segment 16p11.2 — previously reported as a key autism region — are seen in people with developmental delays and speech and behavioral problems, but not necessarily autism. That’s the finding from two large studies published last week of people carrying these rare genetic variations.

The results suggest that variants in the 16p11.2 region — referred to briefly as 16p — must pair with other genetic or environmental factors to cause the full-blown social deficits and stereotyped behaviors seen in autism, the researchers say.

“We are trying to make it clear that the association with autism is there, but also to be open-minded to other conditions that are associated with this rearrangement,” says Marwan Shinawi, an investigator on one of the studies, led by researchers at Baylor College of Medicine in Houston, Texas.

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SFARI, November 2009.

“Suddenly amid the sadness, spiritual darkness and depression, his brain seemed to catch fire . . . like lightning. These glimmerings were still but a premonition of that final second (never more than a second) with which the seizure itself began. That second was, of course, unbearable.”

So wrote Fyodor Dostoevsky in his 1868 novel, The Idiot, describing the seizures suffered by his protagonist. Scientists still don’t know much about what causes these debilitating storms of unchecked electrical activity in the brain. Although many childhood neurological disorders involve seizures, “we don’t have a real handle, developmentally, on models to study them,” notes Gordon Fishell, PhD, professor of cell biology.

But that could be changing. Dr. Fishell and his team have created one such childhood epilepsy model by disrupting the development of specific types of brain cells, called interneurons, in mice. Their findings could offer valuable insights for designing drugs to treat these disorders, which afflict some 123,000 children in the United States each year. “These cells restrict electrical activity in the brain, which, when unrestricted, causes seizures,” explains Dr. Fishell, whose work is funded, in part, by the Simons Foundation. “If we could develop drugs that stimulate those particular cells, we might be able to repress seizure activity.”

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NYU News & Views, November/December 2009.

Genetic analysis of one Belgian family with a history of autism has pinpointed a piece of DNA on chromosome 16, within a segment thought to be missing in about one percent of all cases of autism. The unpublished data was presented on Saturday at the World Congress of Psychiatric Genetics in San Diego.

Three large studies to date have linked autism to a 25 gene-deletion on the short arm of chromosome 161,2,3. In the new work, scientists have identified a boy with autism who’s missing one copy of just five genes in this region. Two of the genes have biological roles in the brain that make them strong candidates for causing the disorder, the researchers say.

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SFARI, November 2009.

The Psychiatric GWAS Consortium, a massive international project aimed at finding common variants in five psychiatric disorders, has released its first batch of analyses, identifying several significant common variations associated with schizophrenia. The results were presented Sunday at the World Congress of Psychiatric Genetics in San Diego.

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SFARI, November 2009.

Scientists have identified several autism-specific variants in a gene that lies within a chromosomal region linked to the disorder, according to a poster presented at the World Congress of Psychiatric Genetics in San Diego.

Interestingly, a closer look at one family tree suggests that some of these variants may be harmless when carried alone but, when inherited together, may lead to autism. The results are in press at the journal Autism Research.

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SFARI, November 2009.

Genetic variations linked to autism and schizophrenia crop up in people with a large variety of conditions, including bipolar disorder, seizures and obsessive-compulsive disorder, as well as in healthy people. This notion gained new support from unpublished data presented Thursday at the World Congress for Psychiatric Genetics in San Diego.

Researchers from Signature Genomics, a private clinical genetic testing company in Spokane, Washington, have found, for instance, that many children with autism inherit deletions in the 16p11.2 chromosomal region — famously linked to autism — from healthy parents with no sign of the disorder.

The findings debunk previous hype that any one variant is crucial for a particular disorder, the researchers say.

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SFARI, November 2009.

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