Why Autism Has a Genetic Side That People Don’t Always Talk About

    When people talk about autism, they sometimes focus only on behavior or the social side of things, but I’ve been learning that genetics actually plays a big role too. I read a study that looked at thousands of families and found that autism has a strong hereditary component, meaning certain traits can be passed down genetically (Grove et al., 2019). That honestly made a lot of sense to me. I’ve known families where multiple people were neurodivergent in different ways, and it never felt like just coincidence. The study pointed out that autism isn’t caused by one single “autism gene,” but rather a mix of many genetic factors that each contribute a small piece. That idea really stuck with me. It shows how complex and diverse autism actually is, and why it looks different in every person.

    Another thing that stood out to me was how genetics interacts with the environment. A second study explained that genetic variations influence how the brain develops, but environment and life experiences can shape how those traits show up (Sandin et al., 2017). I liked that idea because it makes autism feel less like a strict category and more like a blend of biology and lived experience. It also reminded me that being neurodivergent isn’t something a person “chooses” or something caused by bad parenting, which is a harmful stereotype people still repeat. Understanding the genetic side helped me appreciate how naturally varied human brains are. To me, it’s a reminder that neurodivergence isn’t a flaw. It’s just another way of being human, and a lot of that uniqueness starts in our DNA.

References

Grove, J., Ripke, S., Als, T. D., Mattheisen, M., Walters, R. K., Won, H., … & Børglum, A. D. (2019). Identification of common genetic risk variants for autism spectrum disorder. Nature Genetics, 51, 431–444. https://doi.org/10.1038/s41588-019-0344-8

Sandin, S., Lichtenstein, P., Kuja-Halkola, R., Larsson, H., Hultman, C. M., & Reichenberg, A. (2017). The heritability of autism spectrum disorder. JAMA, 318(12), 1182–1184. https://doi.org/10.1001/jama.2017.12141

Can DNA explain the differences between humans and chimps?

Few DNA differences can be seen between our two species. Researchers are looking hard at those differences in hopes of identifying uniquely human stretches of the genome that help science narrow down what makes humans truly human. Two different stretches of DNA were found to be uniquely human that include the genome for larger brains.

One gene was found to not only cause bigger brains but also causes more surface folds as well. It seems to be a characteristic of primarily primates and the human brain. These folds increase the brains surface area which in turn gives more room for neurons to be able to process and store information.   

The Max Planck Institute of Molecular Cell Biology and Genetics in Dresden, Germany, looked for a gene the was only active during the development period of the cortex very early in the embryo development. The cortex that is the thin outer layer of the brain is used to memory, attention, awareness, thought, language, and consciousness.

Researchers found this gene by observing gene activity in an aborted human fetus while comparing it to tissue from a mouse embryo. They identified 56 human genes the mouse tissue lacked.  The most active was a gene called ARHGAP11B, a partial duplication of an existing gene. The duplication arose sometime after human evolution split off from the line that led to chimps some 5 or 6 million years ago. It is uniquely human, being present in Neanderthals and Denisovans, our long-gone kin, as well as anatomically modern humans, the last Homo standing. (That’s us.)

The researchers found out what ARHGAP11B did by putting it into transgenic mice. It doubled the mice’s cortical stem cells and increased their brain size.

https://www.geneticliteracyproject.org/2015/02/20/of-intelligent-mice-and-men-human-genes-give-mouse-bigger-brain/

https://www.geneticliteracyproject.org/2016/03/31/humans-share-99-of-genes-with-chimps-can-dna-explain-differences/

Understanding Family History and its Impact on Genetics

It is safe to say that most people have pondered what it would be like to age more slowly, or halt the aging process altogether. The reality is, we can only learn so many tips and tricks about prolonging our lives from our families and friends. Scientific evidence of the aging process reinforces the fact that we are all going to die some day. This simple fact propels scientists to study all the variables that have an effect on the aging process. Studies show that the lengthier the time our parents are alive; the higher chance we have of living a longer life. If an individual's biological mother or father lived to be over the age of 70, then that individual's risk of an early death drops by 17%. This number gets continuously smaller as his or her parents age of death progresses above 70. Children whose parents have outlived the age of 70 also have a lower risk of developing anemia, high cholesterol, stroke, hypertension, and heart disease in comparison to those offspring whose parents died below the age of 70. Although it is suspected that genetics play the most significant role in understanding a person’s expected life span, there are other factors such as behavior and the environment that come into play.

It is also important for those having children to be conscious of their family's genetic history. Awareness about diseases that have affected an individual's family may help him or her to recognize it in their own child earlier, sometimes preventing a disease from fully progressing. Families share more than just their genetic makeup, they share favorite foods, health habits, and a common environment. Because of this, it is not uncommon for members of a family to exhibit similar health issues. Knowing your history might help you to recognize the likelihood of your child developing certain health problems and get the ones they do have diagnosed sooner rather than later. The earlier you can catch a medical condition or hereditary disease, the better because you wouldn’t want your child to go on suffering or potentially have the condition get worse.

I found this article interesting because even though some of this is common knowledge, many people don’t take the time to understand their family history. Many people go throughout life avoiding visits to the doctor, and some go completely untreated with serious medical issues. Inheriting a harmful disease is obviously not the most ideal situation to be faced with, but it is better to be conscious of these types of things so you can get the proper medical attention when the time strikes. In addition to this, even if you don’t care about your own health, you should be conscious of it in case you ever decide to start a family.

Achondroplasia Awareness

Achondroplasia, a form of short-limbed dwarfism, affects people around the world. It is caused by a mutation in the FGFR3 gene,or fibroblast growth factor receptor 3. This gene is responsible for coding for a protein involved in receiving signals to stimulate bone tissue development. The protein limits bone formation from cartilage, referred to as ossification. When the gene mutates, the body is sent into overdrive, affecting proper bone growth and skeletal formation. 1 out of 15,000 to 40,000 babies have this genetic abnormality.

Inheritance of the achondroplasia gene mutation is autosomal dominant, with two copies of the mutated gene exhibiting an even more severe case of the disease, usually resulting in a stillborn or infant death. Dwarfism displayed in an individual with average-sized parents is the result of a new mutation to the gene.

I have personal experience with this disease, as a close friend grew up with it. He functions almost completely normally in society; doing well and school and even obtaining his driver’s license. His biggest problem is bullying and discrimination from peers, though most friends who grew up with him are completely accepting of his condition. Maybe drawing attention to this disease will be able to eliminate bullying and stereotypes that surround dwarfism and other genetic disorders. Hopefully advancements in science will eventually result in treatment or a cure, but until then a short time fix could be eliminating ignorance about this disease.

Genes: The answer to the mental health problem?

As an EMT I witness numerous people weekly that suffer from severe mental illness. It seems that the treatment methods that are currently available are, at best, insufficient. Many hospitals are ill prepared to treat the mind and training in most health care works is a single piece to a one thousand piece puzzle. Mental health treatment needs a breakthrough, perhaps ones that will come from genetics. Researchers have recently found a genetic link between schizophrenia, biopolar disorder, autism, major depressive disorder, and attention deficit hyperactivity disorder. It was shown that there are some genetic “glitches” present in the population suffering from these mental illnesses. Researchers seem to believe that the presence of these genes leads to a predisposition to these illnesses; however, other factors also play an important role.

Researchers were able to find disruptions in some of the brain’s major signaling pathways. This new information may aid in the development of new treatments. It has also been determined that the same change in the DNA in very close family members can result in two very different diseases. Four genes have been marked as possibly having an effect on mental health. In two the causality of the disorder is unknown; however, two of the genes have been shown to be a part of calcium channels. Calcium channels are used in the brain in order to transmit signals.

There already drugs on the market that effect the calcium channels. These drugs are currently used to treat high blood pressure. A doctor at Massachusetts General Hospital is currently working to seek approval to experiment using calcium channel blockers currently used as high blood pressure medications to treat mental illnesses. This study has the potential to open many new doors for treatment of mental illness, something that this country truly needs.

Original Article: http://www.nytimes.com/2013/03/01/health/study-finds-genetic-risk-factors-shared-by-5-psychiatric-disorders.html

Blog on Same Topic: http://www.health.harvard.edu/blog/shared-genes-link-depression-schizophrenia-and-three-other-mental-illnesses-201303015944