The role of reduced expression of fragile X mental retardation protein in neurons and increased expression in astrocytes in idiopathic and syndromic autism (duplications 15q11.2‐q13)
Caption: Pictures of the frontal cortex of people with autism without a dup15q mutation, those with a 15q mutation and autism, and those without autism, stained to reveal the FMRP protein. Courtesy of Jarek Wegiel, IBR
So different, but so much the same
Summary of original publication by: Alycia Halladay, Edwin Cook, Vanessa Vogel-Farley
Autism is diagnosed in about 80% of people with Dup15q (maternal duplication of the 15q11-q13 region), making it a key gene in the understanding of this disorder. For most people with autism, a mix of different genes and environmental factors led to a diagnosis. However, in people with Dup15q, a key region on chromosome 15 is largely responsible. Researchers are using this to both better understand autism, and develop targeted therapies which may help those even without a mutation in chromosome 15.
To understand what goes on in the brains of people with autism, scientists have to study the brains of people with autism. By doing this, they have discovered that except for that key region of chromosome 15, the genes in the brains of people with autism with Dup15 and without Dup15 are largely similar (reference). Recently, researchers at the Institute of Basic Research in NY have discovered that a key protein called FMRP is equally missing in the brains of people with autism and Dup15 compared to those with autism but without this mutation. This protein is involved in the development and growth of brain cells, as well as the ability of the brain cells to change shape and function during development and adulthood. The lack of this protein is also associated with smaller size of brain cells, as well as the irregular connection of neurons (which communicate information to eachother) to astrocytes (which provide structural support to neurons). The pattern of FMRP in brain cells looked more like those that are seen in much younger ages.
Interestingly, FMRP is a protein missing in another syndrome associated with autism called Fragile X syndrome. These findings show that there are similar brain changes across autisms with a known genetic cause and those with multiple genetic and environmental causes. This opens up the possibility of expanding therapies developed for people with Dup15 to other types of autism, and also provides some biological basis to the common set of behavioral features and deficits together known as autism.
Check out this recent article from Autism Brain Net that details the use of donated brain tissue to study autism. For more information about brain donation and why it’s important, please visit: https://www.autismbrainnet.org/donors-family/
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