Autism, a disorder that involves impairment in social interactions and communication, affects millions of people, and the number is growing. The cause of autism is still unknown, and therefore its treatment is unknown. However, new discoveries in science are illuminating how the brains of people with autism are different than neurotypical brains. New research has found that neurons in people with autism are different from others’ neurons.
Autism, as stated above, is a neurodevelopmental disorder in which people process social interactions and communications differently. While the cause is unknown, this disorder is highly inheritable. Symptoms include reduced eye contact, reduced language skills, difficulty communicating, and difficulty understanding and communicating emotions. People with autism often have stereotyped, repetitive behavior, like hand-wringing. One of the most difficult aspects of researching autism is how variable its course is. In some people, the differences are obvious. In others, they are more subtle. Even the genes that have been correlated with autism vary. Genes associated with autism are expressed in multiple types of neurons at multiple time points in the neuron’s life cycle. This is a part of what makes studying the genetic aspect of autism so difficult.
What is a neuron?
A neuron is the nerve cell that helps the body communicate with the brain. A neuron has a body, dendrites, and an axon. The dendrites are filaments that process incoming data from other cells. The axon is a filament that carries information from the neuron to other cells. Neurons are special. There is no other cell in the body like them. They are slow growing and do not replicate as easily as other cells in the body.
There are three types of neurons: sensory neurons, motor neurons, and interneurons. Sensory neurons respond to the senses: touch, smell, vision, sound, etc. Motor neurons are self-explanatory and are responsible for movement. Interneurons connect neurons to other neurons, the middle men of information.
How are the neurons found in autism different?
Simon Shafer, the lead researcher in this study from the Salk Institute, examined skin cells from people with and without autism. He transformed those skin cells into stem cells, a type of cell found in the body that can transform into any other type of cell. He then turned that stem cell into a nerve cell, a neuron. He found that the cells from those with autism grew larger than those without. They grew longer and more complex branching patterns.
Beyond size and complexity, Shafer also found genetic abnormalities in the autism-derived cells. For example, a gene found in all of the cells switched on faster in the cells from autistic people. Additionally, the autistic-derived cells had idiosyncracies when forming their genetic material. Chromatin, tightly packed genetic material, was looser in the autistic-derived neuronal stem cells than it is in neurotypical cells. This makes the chromatin more “accessible”, easier to make genetic changes. This open chromatin can cause major changes in neuronal development. Because of this finding, the scientists believe that this early development stage of the neuronal stem cell is key in the development of autism. They argue that this might signify that autism is caused by early changes in genetic material in developing neuronal stem cells. However, this is just one finding in a complicated disorder.
This work builds on previous research into the causes of autism. One large-scale postmortem study found consistent transcriptome changes, a type of DNA precursor, that occur during the first decade of brain development. These two studies together bolster the claims that autism is both genetically related and related to early brain development.
While these findings are exciting, it is important to note that no research study is absolute. In fact, this research study used cells from autistic people with enlarged brains. Not all autistic people have enlarged brains. Therefore, this only represents one cohort of people with autism. The authors argue that this cohort represent a large proportion of those with Autism Spectrum Disorder, but this is still only one population on an entire spectrum.
Autism is a complicated disorder that encompasses an entire spectrum of behaviors and difficulties processing social interactions. It is an area of intense and exciting research. The findings from the Salk Institute reflect one more study in a long list. Shafer’s work is particularly promising because it highlights the role of abnormal stem cells in the development of autism. This may lay the groundwork for researching how normal stem cells may help alleviate some of the symptoms of autism. If you would like to learn more about how stem cells may help you or a loved one with autism spectrum disorder, contact the Stem Cell Transplant Institute today.