A recent new study by Professor Valerie Hu, at the George Washington University (GW) School of Medicine and Health Sciences (SMHS), identified a regulatory gene that controls a large number of other genes associated with autism. The gene is called RORA.
“We are focusing on this gene, in part, because this gene can act as a master regulator of other genes,” said Hu, whose study was published in the journal Molecular Autism. “Called nuclear hormone receptors, they are capable of activating or suppressing other genes in the genome. The question was which specific genes are regulated by RORA.”
Her research demonstrated that RORA encodes a protein that regulates the expression of more than 2,500 other genes. Of these 2,500 genes, many are known to be involved in neuronal development and functions, and 426 of RORA’s gene targets are already listed in AutismKB, a database of known autism candidate genes.
“We see it as a domino effect, where RORA is a particularly shaky domino,” said Hu. “If knocked over, it can also knock down a whole bunch of other genes, except that it’s not just a single chain of events. There are multiple chains of events, leading to massive disruption of gene expression in autism.”
An earlier 2011 study by Hu’s group demonstrated that RORA could influenced by negative and positive regulation of androgen and estrogen, respectively, suggesting that RORA may also contribute to the male bias of autism spectrum disorder.
Other research groups have suggested that they have only identified 10% of the genes responsible for the biochemical pathway associated with Autism, according to Joseph Buxbaum, PhD, Director of the Seaver Autism Center and Professor of Psychiatry, Genetics and Genomic Sciences, and Neuroscience at Mount Sinai School of Medicine. His group identified mutations in three new genes that were directly linked to autism.
The genes with mutations identified in the studies — CHD8, SNC2A, and KATNAL2 — were discovered with a new state-of-the-art genomics technology known as exome sequencing, where all protein coding regions of the genome, called the exome, are analyzed. The researchers say that with further characterization of the genes and sequencing of genes in thousands of families, they will be able to develop novel therapeutics and preventive strategies for autism.
Tewarit Sarachana, Valerie W Hu. Genome-wide identification of transcriptional targets of RORA reveals direct regulation of multiple genes associated with autism spectrum disorder. Molecular Autism, 2013; 4 (1): 14 DOI: 10.1186/2040-2392-4-14.
Stephan J. Sanders, Michael T. Murtha, Abha R. Gupta, John D. Murdoch, Melanie J. Raubeson, A. Jeremy Willsey, A. Gulhan Ercan-Sencicek, Nicholas M. DiLullo, Neelroop N. Parikshak, Jason L. Stein, Michael F. Walker, Gordon T. Ober, Nicole A. Teran, Youeun Song, Paul El-Fishawy, Ryan C. Murtha, Murim Choi, John D. Overton, Robert D. Bjornson, Nicholas J. Carriero, Kyle A. Meyer, Kaya Bilguvar, Shrikant M. Mane, Nenad Šestan, Richard P. Lifton, Murat Günel, Kathryn Roeder, Daniel H. Geschwind, Bernie Devlin, Matthew W. State. De novo mutations revealed by whole-exome sequencing are strongly associated with autism. Nature, 2012; DOI: 10.1038/nature10945