New Information on Autism and Genetics

Research out of the George Washington University reveals another piece of the puzzle in a genetic developmental disorder that causes behavioral diseases such as autism.
"It tell us that in very early development, those with 22q11.2 deletion syndrome do not make enough cells in one case, and do not put the other cells in the right place. This occurs not because of some degenerative change, but because the mechanisms that make these cells and put them in the right place during the first step of development have gone awry due to mutation,"said LaMantia.

Science Daily - Jan. 3, 2013
T. M. Maynard, et.al.
A comprehensive analysis of 22q11 gene expression in the developing and adult brain. 

Proceedings of the National Academy of Sciences, 2003; 100 (24): 14433 DOI:10.1073/pnas.2235651100

Neuronal reference frames for social decisions in primate frontal cortex

Steve Chang et. al. studied encoding of the outcomes of social decisions in three frontal cortical areas as monkeys performed a social reward allocation task. Orbitofrontal cortex neurons signaled received rewards, anterior cingulate (ACC) sulcus neurons signaled foregone rewards, and the ACC gyrus was involved in the computation of shared experience and social reward.
Nature Neuroscience (2012) doi:10.1038/nn.3287

Whole-Genome Sequencing in Autism Identifies Hot Spots for De Novo Germline Mutation

An international team, led by researchers from UC San Diego,  has discovered that "random" mutations in the genome are not quite so random after all. Their study, to be published in the journal Cell on December 21, shows that the DNA sequence in some regions of the human genome is quite volatile and can mutate ten times more frequently than the rest of the genome. Genes that are linked to autism and a variety of other disorders have a particularly strong tendency to mutate.
Science Daily, Dec 20, 2012
Jacob J. Michaelson et al.
Cell, Volume 151, Issue 7, 1431-1442, 21 December 2012

Synaptic scaffold evolution generated components of vertebrate cognitive complexity

The origins and evolution of higher cognitive functions, including complex forms of learning, attention and executive functions, are unknown. A potential mechanism driving the evolution of vertebrate cognition early in the vertebrate lineage (550 million years ago) was genome duplication and subsequent diversification of postsynaptic genes. Here the authors report the first genetic analysis of a vertebrate gene family in cognitive functions measured using computerized touchscreens. Comparison of mice carrying mutations in each of the four Dlg paralogs showed that simple associative learning required Dlg4, whereas Dlg2 and Dlg3 diversified to have opposing functions in complex cognitive processes. Exploiting the translational utility of touchscreens in humans and mice, testing Dlg2 mutations in both species showed that Dlg2's role in complex learning, cognitive flexibility and attention has been highly conserved over 100 million years. Dlg-family mutations underlie psychiatric disorders, suggesting that genome evolution expanded the complexity of vertebrate cognition at the cost of susceptibility to mental illness.
Jess Nithianantharajah, et al.
Nature Neuroscience 16, 16–24 (2013) doi:10.1038/nn.3276

Disorder of Neuronal Circuits in Autism Is Reversible, New Study Suggests

People with autism suffer from a pervasive developmental disorder of the brain that becomes evident in early childhood. Peter Scheiffele and Kaspar Vogt, Professors at the Biozentrum of the University of Basel, have identified a specific dysfunction in neuronal circuits that is caused by autism. In the journal Science, the scientists also report about their success in reversing these neuronal changes. These findings are an important step in drug development for the treatment for autism.Science

Daily Sept 22, 2012
Stéphane J. Baudouin, et al.

Shared Synaptic Pathophysiology in Syndromic and Nonsyndromic Rodent Models of Autism. Science, 13 September 2012 DOI: 10.1126/science.1224159

Interneuron dysfunction in psychiatric disorders

Schizophrenia, autism and intellectual disabilities are best understood as spectrums of diseases that have broad sets of causes. However, it is becoming evident that these conditions also have overlapping phenotypes and genetics, which is suggestive of common deficits. In this context, the idea that the disruption of inhibitory circuits might be responsible for some of the clinical features of these disorders is gaining support. Recent studies in animal models demonstrate that the molecular basis of such disruption is linked to specific defects in the development and function of interneurons — the cells that are responsible for establishing inhibitory circuits in the brain. These insights are leading to a better understanding of the causes of schizophrenia, autism and intellectual disabilities, and may contribute to the development of more-effective therapeutic interventions.

Oscar Marín
Nature Reviews Neuroscience 13, 107-120 (February 2012) |doi:10.1038/nrn3155