{"id":4625,"date":"2015-01-21T14:04:03","date_gmt":"2015-01-21T19:04:03","guid":{"rendered":"http:\/\/geiselmed.dartmouth.edu\/news\/?p=4625"},"modified":"2015-02-10T11:04:10","modified_gmt":"2015-02-10T16:04:10","slug":"new-study-sheds-light-on-genetic-mutations-in-autism-disorders","status":"publish","type":"post","link":"https:\/\/geiselmed.dartmouth.edu\/news\/2015\/new-study-sheds-light-on-genetic-mutations-in-autism-disorders\/","title":{"rendered":"New Study Sheds Light on Genetic Mutations in Autism Disorders"},"content":{"rendered":"

Recent research has linked autism with a lack of \u201cpruning\u201d in developing brain connections, but a new study by researchers at Dartmouth's Geisel School of Medicine suggests instead it is the excessive growth of new connections that causes sensory overload in people with the disorder.<\/p>\n

The results, which have\u00a0broad implications for understanding the neurobiological basis of\u00a0autism spectrum disorders,\u00a0appear in\u00a0The Journal of Neuroscience<\/em><\/a>.\u00a0The study was authored Michael Williams, PhD, Allan Gulledge, PhD, and Bryan Luikart, PhD, in Geisel\u2019s Department of Physiology and Neurobiology.<\/p>\n

\"Bryan
Bryan Luikart, PhD<\/figcaption><\/figure>\n

\u201cWe\u2019ve been working on understanding how dysfunction of\u00a0the gene Pten, which is known to cause some cases of autism, effects neuronal development, and\u00a0I believe our findings represent the best understanding in science today for how an autism candidate gene changes the functional characteristics of developing neurons,\u201d says senior author\u00a0Bryan Luikart<\/a>, an\u00a0assistant professor of Physiology and Neurobiology.<\/p>\n

Mutations in the gene Pten are among the most common single-gene mutations that cause autism and a group of interrelated syndromes. People with these diseases have increased chances of having autism, intellectual disability and epilepsy. Luikart\u2019s team is investigating the neurobiological basis of the complex symptoms of autism by modeling genetic changes associated with autism in humans in neurons of mice. For their new study, the researchers generated a model in which they injected retroviruses into the brains of developing mice to both knockout the Pten gene and to label the knockout neurons with a fluorescent marker. This allowed them to study how turning off the gene alters the structural and electrical development of the neurons. They found that knocking out the Pten gene caused overt overgrowth of the neurons, which resulted in an increase in the number of excitatory synapses, or the connections that transmit signals from a nerve cell to another cell.\u00a0 The ultimate result of this is that the neurons become hyperactive.<\/p>\n

Recent media coverage has surrounded the idea that autism is associated with a lack of \u201cpruning\u201d or refinement of excitatory synapses later in development. But the Dartmouth study argues against this, saying it is not a failure of \u201cpruning\u201d that results in the ultimate increase in excitatory synapses, but an increase in new production of excitatory synapses. Further, they found a tight interrelationship between the structural and functional changes produced by the Pten gene knockout.<\/p>\n

\u201cThe broader implication for this is that mutations in the gene Pten in humans likely result in an increased developmental proliferation of excitatory synaptic connections,\u201d Luikart says. \u201cThis may result in a given sensory experience stimulating neurons or even whole brain regions that would never be excited in a normal brain. Conceptually, this could be the neurobiological basis for the inappropriate responses to sensory stimulation that is often characteristic of patients with autism.\u201d<\/p>\n","protected":false},"excerpt":{"rendered":"

Recent research has linked autism with a lack of \u201cpruning\u201d in developing brain connections, but a new study by researchers at Dartmouth’s Geisel School of Medicine suggests instead it is the excessive growth of new connections that causes sensory overload in people with the disorder. <\/p>\n","protected":false},"author":15,"featured_media":4626,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_publicize_message":"","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":true,"jetpack_social_options":{"image_generator_settings":{"template":"highway","default_image_id":0,"font":"","enabled":false},"version":2}},"categories":[1,8],"tags":[499,498,500,320],"class_list":["post-4625","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-news","category-research","tag-autism-genetics","tag-bryan-luikart","tag-pten","tag-research-2","author-15"],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"https:\/\/geiselmed.dartmouth.edu\/news\/wp-content\/uploads\/sites\/2\/2015\/01\/luikart_autism.jpg","jetpack_sharing_enabled":true,"jetpack_shortlink":"https:\/\/wp.me\/p4r3h1-1cB","_links":{"self":[{"href":"https:\/\/geiselmed.dartmouth.edu\/news\/wp-json\/wp\/v2\/posts\/4625","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/geiselmed.dartmouth.edu\/news\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/geiselmed.dartmouth.edu\/news\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/geiselmed.dartmouth.edu\/news\/wp-json\/wp\/v2\/users\/15"}],"replies":[{"embeddable":true,"href":"https:\/\/geiselmed.dartmouth.edu\/news\/wp-json\/wp\/v2\/comments?post=4625"}],"version-history":[{"count":3,"href":"https:\/\/geiselmed.dartmouth.edu\/news\/wp-json\/wp\/v2\/posts\/4625\/revisions"}],"predecessor-version":[{"id":4630,"href":"https:\/\/geiselmed.dartmouth.edu\/news\/wp-json\/wp\/v2\/posts\/4625\/revisions\/4630"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/geiselmed.dartmouth.edu\/news\/wp-json\/wp\/v2\/media\/4626"}],"wp:attachment":[{"href":"https:\/\/geiselmed.dartmouth.edu\/news\/wp-json\/wp\/v2\/media?parent=4625"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/geiselmed.dartmouth.edu\/news\/wp-json\/wp\/v2\/categories?post=4625"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/geiselmed.dartmouth.edu\/news\/wp-json\/wp\/v2\/tags?post=4625"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}