The most common form of heritable cognitive impairment is Fragile X Syndrome, caused by mutation or malfunction of the FMR1 gene. Loss of FMR1 function is also the most common genetic cause of autism. Understanding how this gene works is vital to finding new treatments to help Fragile X patients and others. Researchers from the Perelman School of Medicine at the University of Pennsylvania, and colleagues from Brown University, have identified the FMRP protein (encoded by FMR1) as a key player in RNA editing, a process in which the working copies made from DNA, called messenger RNAs, are chemically altered after being transcribed from the genome. Their findings were published online this week in Nature Neuroscience. Since RNAs are used as the instructions to make proteins, mistakes in RNA editing at the neuromuscular junction (NMJ), the site at which motor neurons innervate muscle, may cause problems in nerve function.
A small study found that male children with autism had larger brain weights and 67% more prefrontal brain neurons than children without autism, scientists from the NIH-UCSD School of Medicine Autism Center of Excellence, La Jolla, Calif., reported in JAMA (Journal of the American Medical Association). The small preliminary study compared 7 children with autism to 6 healthy controls - they were aged from 2 to 16 years. The authors explained that head overgrowth and larger brain size are evident in children with autism. Neural dysfunctions have been identified in several brain regions, including PFC (prefrontal cortex). This part of the brain plays a key part in communication, cognitive development, and higher-order social development. As background information, the scientists wrote: "Therefore, knowledge of the neural basis of overgrowth could point to early causal mechanisms in autism and elucidate the neural functional defects that engender autistic symptoms.
Autism Spectrum Disorder (ASD) affects about 1 in 100 children resulting in a range of problems in language, communication and understanding other people's emotional cues, all of which can lead to difficulties in social situations. Boys are three to four more times as likely to be affected as girls and consequently it has been suggested that the genes involved in this disorder may be linked to the X chromosome. New research published in BioMed Central's open access journal Molecular Autism used genome wide association study (GWAS) data to find a variation in the gene for transducin Ã -like 1X-linked (TBL1X) which is associated with increased risk of ASD in boys. A team of researchers across America combined three sets of genomic data incorporating over 3000 affected children and their family members or non-related case control individuals.
Scientists at the University of Massachusetts Medical School are the first to map epigenetic changes in neurons from the brains of individuals with autism, providing empirical evidence that epigenetic alterations - changes in gene expression caused by mechanisms other than changes in the underlying DNA sequence - may play an important role in the disease. Analysis of these variations revealed hundreds of genetic sites that overlap with many of the genetic regions known to confer risk for Autism Spectrum Disorders. The study was published in Online First by the Archives of General Psychiatry. Autism spectrum disorders are a group of complex biological illnesses with a variety of origins. People with a disorder on the autism spectrum often struggle with social interactions and communication.
Neurons change at various sites across the genome in the prefrontal cortex of people with autism, researchers from the University of Massachusetts Medical School, Worcester, reported in Archives of General Psychiatry. The scientists said they identified changes in chromatin structures at hundreds of locations across the genome. Chromatin is essentially the substance of chromosomes. ASDs (autism spectrum disorders) are a group of complex disorders with different origins and causes. The authors explained that neuronal abnormality in the cerebral cortex and other brain regions may impact on the behavioral and cognitive defects present in autism. A neuron is a nerve cell. Neurons send and receive electrical signals over long distances inside our bodies. Hennady P. Shulha, Ph.D. and team examined postmortem brain tissue of 16 people aged between 2 and 60 years;