A new study of nearly 1,000 people with autism confirmed that the genetic disease are much more idiosyncratic than some had thought . Instead of a few genes that increase the risk of autism in the population, scientists found dozens of genes that drive the disease, many of them in just one or two people. It seems that these variants share certain characteristics, however. Many are involved in cell proliferation and cell signaling in the brain
Although scientists are encouraged by this new map of the genetics of autism, they also say they have a long way to browse to discern how these genetic changes cause this particular disease.
in recent years, researchers studying autism and schizophrenia have found that the genomes of patients either are riddled with so-called copy number variants or deletions duplication of DNA segments that can include many genes. Indeed, the most dramatic of these variants in the number of copies are still visible with a microscope, as abnormalities in the chromosomes of children with undiagnosed developmental disability. Some of these pathogens changes occur spontaneously during embryonic development, while others are inherited.
The latest study, published online today in Nature , is the second phase of the Autism Genome Project Consortium, which includes more than 0 scientists in 11 countries in North America and Europe. (The first, published in 07 in Nature Genetics was a broad analysis of genetic changes and copy number variation, with fewer families and less detailed analysis of number of rare variants copies.) Here scientists scanned the genomes of 996 children with autism spectrum disorders, a group of conditions that affect social and communication skills, high resolution and compared them with children Parents of genomes and to 1287 people without the disease .
just over 5% of individuals had at least a "de novo" varying number of copies that appeared in the sperm cell or egg cell forming the embryo, or spontaneously in the fertilized egg . And number of copies inherited from relatives variants were also much more common in autistic cohort: Overall, rare variations in copy number were 19% more likely to disrupt genes in autistic children than controls
gene deletions had. great effect. Almost all of them were extremely rare showing in, at most, a handful of families. "Most people who have autism will have their own rare form," genetically speaking, says lead author Stephen Scherer, a geneticist at the Hospital for Sick Children in Toronto, Canada.
That said, the team found that genes deleted in autistic patients tended to perform similar tasks. Many have been involved in aspects of cell proliferation, such as the formation of an organ. A number have participated in the development of the central nervous system and other in maintaining the cytoskeleton, which protects the cell and help to move.
"Those are not shots randomly in the genome" and clearly have a link with autism, says Jonathan Sebat, a geneticist at Cold Spring Harbor Laboratory in New York state. First, "you look at it and immediately became fascinated," he said, especially because when it comes to genetic analysis, autism is behind other psychiatric disorders because studies have was lower. at the same time, they are subject to the same types of genes involved in schizophrenia and related illnesses, he says, to understand how they cause autism will probably be difficult.
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