New formula for identifying disorder at younger age could mean earlier therapy, better tests
A Toronto research team has identified the formula for diagnosing autism spectrum disorder (ASD) at an earlier age. This will let patients receive therapies at an earlier age, while helping to create more advanced genetic diagnostic tests.
Published recently in Nature Genetics, the research unravels the autism code by creating a “genetic formula” that will help clinicians identify genetic mutations that have the highest and lowest likelihood of causing ASD.
The work was led by molecular genetics professor Stephen Scherer, who is director of the McLaughlin Centre for Molecular Medicine at the University of Toronto and director of The Centre for Applied Genomics at The Hospital for Sick Children.
“In our new study we’ve finally discovered a unifying set of characteristics in the DNA that we can weave into a ‘genetic formula’ that helps us calculate which genetic mutations have the highest probability of causing autism, and equally important, which alterations do not have a role,” Scherer said.
Scientists have identified around 100 genes that are linked to ASD. However, depending on how these genes mutate it may or may not lead to the disorder. Scientists needed a formula that could more accurately predict which gene permutations would cause ASD.
Dr. Mohammed Uddin, a postdoctoral fellow on Scherer’s team, found that the key to the autism mutation code lies in recognizing small segments of genes – called exons – that are both “highly conserved” in human evolution and “turned on” during early brain development. Scherer’s team identified almost four thousand such brain exons in more than seventeen hundred different genes.
“The timing of this gene activation is an important finding. The fact that these genes could be turned on prenatally gives us a clue as to when autism could start to develop,” said Scherer.
Scherer predicts that many of the novel genes discovered by his group will eventually be found to be involved in autism, intellectual disability or other related medical conditions associated with brain development or cognition.
“This groundbreaking work will have immediate impact on efforts to develop more accurate genetic diagnostic tests aimed at improving earlier detection and clinical decisions to begin intervention,” said Dr. Robert Ring, chief scientific officer of Autism Speaks.
Scherer, who holds the GlaxoSmithKline-Canadian Institutes of Health Research Chair in Genetics and Genomics at U of T SickKids, recently led an international group of scientists that developed a new genetic “guidebook” for autism diagnosis.
Source of text: Liam Mitchell, U of T News
Original Research Article: Uddin M, Tammimies K, Pellecchia G, Alipanahi B, Hu P, Wang Z, Pinto D, Lau L, Nalpathamkalam T, Marshall CR, Blencowe BJ, Frey BJ, Merico D, Yuen RK, Scherer SW. Brain-expressed exons under purifying selection are enriched for de novo mutations in autism spectrum disorder. Nat Genet. 2014 May 25. doi: 10.1038/ng.2980.
