For decades, autism researchers have faced a baffling riddle: how to unravel a disorder that leaves no known physical trace as it develops in the brain. A new UCLA study, published May 25 in the advance online edition of Nature, is the first to reveal how autism makes its mark at the molecular level, resulting in a brain that differs dramatically in structure from a healthy one. The study provides new insight into how genes and proteins go awry in autism to alter the mind. It also identifies a new line of attack for researchers, who currently face a vast array of potential fronts for tackling the neurological disease and identifying its diverse causes. The researchers compared brain tissue samples obtained after death from 19 autism patients and 17 healthy volunteers. After profiling three brain areas previously linked to autism, the group zeroed in on the cerebral cortex, the most evolved part of the human brain. The researchers focused on gene expression: how a gene’s DNA sequence is copied into RNA, which directs the synthesis of cellular molecules called proteins. Each protein is assigned a specific task by the gene to perform in the cell. By measuring gene-expression levels in the cerebral cortex, the team uncovered consistent differences in how genes in autistic and healthy brains encode information. The researchers’ next step was to identify the common patterns. To do this, they looked at the cerebral cortex’s frontal lobe, which plays a role in judgment, creativity, emotions and speech, and at its temporal lobes, which regulate hearing, language and the processing and interpreting of sounds. When the scientists compared the frontal and temporal lobes in the healthy brains, they saw that more than 500 genes were expressed at different levels in the two regions. In the autistic brains, these differences were virtually non-existent.
Autism is a complex brain disorder that strikes in early childhood. The disease disrupts a child’s ability to communicate and develop social relationships and is often accompanied by acute behavioral challenges. In the U.S., autism spectrum disorders are diagnosed in one in 110 children. The UCLA Center for Autism Research and Treatment provides diagnosis, family counseling, clinical trials and treatment for patients with autism. UCLA is one of eight centers in the National Institutes of Health–funded Studies to Advance Autism Research and Treatment network and one of 10 original Collaborative Programs for Excellence in Autism.
UCLA neural stem cell research might benefit patients with stroke and autism
New UCLA study: Can traumatic memories be erased?
Smoking impacts teens’ brains, UCLA study reports
New UCLA microscope studies the brain in 3-D
UCLA study finds structural brain alterations in women with irritable bowel syndrome