BioQuakes

AP Biology class blog for discussing current research in Biology

Tag: Autism

New Research Shows Possible Early Diagnosis of Autism

Normally autism in children is diagnosed at around ages two or three but studies have been done to try to predict autism before behavioral symptoms occur.  University of North Carolina partnered with other universities to experiment with MRI machines to see if they could diagnose autism earlier than 24 months (2 years)

Autism is a big problem in our country and the rest of the world.  About 3 million people have autism in the United States and millions more throughout the world.  The study focused on hyper-expansion of brain surface area in children of 6-12 months of age. According to this article “Brain overgrowth was tied to the emergence of autistic social deficits in the second year.” They found that 8 out of 10 kids with a hyper-expanded brain as well as an autistic sibling would be diagnosed with autism in the future.

The fact that MRI’s can show enlarged surface area of the brain at such a young age is important in predicting whether or not a child will be later diagnosed with autism.  This is an important experiment because if doctors can predict autism before symptoms occur there may be ways for them to intervene with brain growth before a child’s brain permanently has autism and behavioral changes occur at 24 months.

 

 

MRIs Catch Autism Prior to Symptoms

Mark Lythgoe & Chloe Hutton / Wellcome Images Image Link

Research

By using magnetic resonance imaging (MRI), researchers are now able to accurately study and predict which infants, among those with older autistic siblings, will be diagnosed by the age of 2. According to an article on Science daily, in the past couple of years, researchers have correctly predicted 80 percent of these infants who would later meet criteria for autism at 24 months of age.

A study published in Nature, shows how early brain biomarkers can be very beneficial in identifying infants at the highest risk for autism prior to any symptoms. Joseph Piven, professor of Psychiatry at the University of North Carolina-Chapel Hill, explains how typically autism cannot be detected in infants until they ages 2-4, but for infants with autistic siblings, it can be determined at an earlier age.

People diagnosed with Autism Spectrum Disorder (ASD), experience social deficits and  demonstrate very specific stereotypical behaviors. According to this study, it is estimated that one out of 68 children develop autism in the United States and that  for infants with older siblings with autism, the risk may be as high as 20 out of every 100 births. Despite these high numbers, it remains a difficult task to detect behavioral symptoms prior to 24 months of age.

Piven, along with a couple of other researchers, conducted MRI scans of infants at six, 12, and 24 months of age. They discovered that increased growth rate of surface area in the first year of life was linked to increased growth rate of overall brain volume in the second year of life. This meant that brain overgrowth was tied to the emergence of autistic social deficits in the second year. The researchers then took the information they had and used a computer program that classified babies most likely to meet criteria for autism at 24 months of age, and developed an algorithm that they applied to a separate set of study participants.

The researchers found that there were brain differences at 6 and 12 months of age in infants with older siblings with autism and infants with older ASD siblings who did not meet criteria for autism at 24 months.

Plans for the Future

This research and test would be very beneficial to a family who already has a child with autism and has a second child who may or may not be affected. The ideal goal would be to intervene and provide as much assistance to the infant and family prior to the emergence of symptoms. By intervening at early stages and when the brain is most susceptible, researchers hope to improve the outcomes of treatment.

In the nature study, Piven describes how Parkinson’s and Autism are similar in that when the person is diagnosed, they’ve already lost a substantial portion of the dopamine receptors in their brain, making treatment less effective.

One mother who has benefitted from this discovery and is extremely grateful is Rachel O’Connor. When interviewed by News12, she shared how early intervention “has brought out some language in [her] daughter,” and how her daughter “can now say what she wants and she desires. She makes better eye contact.”

 

The Human Gut Microbiome and Autism Spectrum Disorders

Researchers of the human gut microbiome have made connections to the autism spectrum disorder.  A gut microbiome involves the digestive tract microbes.  To learn more general information click here.  Studies tested DNA of children with gastrointestinal complaints.  Researches compared children with Autism Spectrum Disorder, and mainstream children.  It was found that children with Autism Spectrum Disorder had too many Clostridium or Desulfovibrio clusters.  To learn more about these gene clusters click here. Developing fever, receiving oral antibiotics, or ingesting probiotics are all likely to alter the gut microflora.  When children with Autism Spectrum Disorder do the above, they have exhibited improvement in their gastrointestinal pains; however, there hasn’t been scientific research, as it has only been found anecdotally. Research has been limited due to the difficult culture-dependent techniques; however, metagenomic technology could be used to discover and reduce the effects of the gut microbiome as a part in Autism Spectrum Disorder.

A longitudinal study completed in May 2016 shows more progress that scientists have made in discovering different aspects of autism in relation to the microbiome.  For two weeks, stool samples were collected from patients with autism and their siblings without autism in order to be compared. Sarcina ventriculi, Barnesiella intestihominis, and Clostridium bartlettii are organisms that are related to autism. They were found in the stool samples of children with autism, but not their siblings. Gastrointestinal symptoms were reported on days 6-8 of the study for children with Autism Spectrum Disorder, where Haemophilus parainfluenzae was detected at the onset. These patients also exhibited behavioral challenges during these days.

Though scientists have not found a diagnosis for Autism Spectrum Disorder yet, it is clear that the gut microbiome plays a role in the development. Further research that is not merely based off of a handful of patients needs to be completed to learn more.

Photo of Gut Flora

New Discoveries Link Stomach Bacteria with Autism

Autism rates are on the rise in the US, and the cause of this condition is still unknown.  Autism is mental condition, present from early childhood, characterized by difficulty in communicating and forming relationships with other people and in using language and abstract concepts.  According to the CDC, 1 in 68 children will be born with autism.  This is a huge increase from the 1 in 150 children in 2000.  It is unknown how autism starts, but something causes a change in brain structure or function that leads to the condition.  New research shows that it could possibly be related to the human gut microbiome.

Mycobacterium tuberculosis Bacteria, the Cause of TB

Image Source

Since the 1990’s, the gut microbiome has been the topic of copious amounts of research.  Scientific developments since then have uncovered the influence that the gut microbiome has on human health.  Disorders in the microbiome have been linked to conditions like asthma, rheumatoid arthritis and even some cancers.  New research claims that over representation of Clostridium or Desulfovibrio bacteria in the microbiome could possibly cause the autism spectrum disorders.  According to the report, “Studies of fecal DNA extracts have found Clostridium or Desulfovibrio clusters over-represented in children with gastrointestinal complaints and ASD(autism spectrum disorders) as compared to children with similar GI complaints but typical neuro-behavioral development”.  A another possible link between the microbiome and autism was found when clinical improvement was reported in children with autism who developed fever, received antibiotics, or ingested probiotics— treatments that likely altered gut bacteria, thus limiting the effects of the bacteria. 

While the connections may be weak right now, discovering potential connections between autism and the gut microbiome allows for more research and a potential cure one day.  One researcher plans on conducting a clinical study using fecal transplants from healthy donors. The goal of this study is to see if the treatment “would reduce autism symptoms by normalizing an individual’s community of gut bacteria.”

Original Article

Further Reading:

https://www.autismspeaks.org/science/science-news/autism-study-more-evidence-linking-altered-gut-bacteria-asd

 

The Movie of Autism

Stacking repetitively is a behavior often associated with Autism

According to a recent study, “children with autism spectrum disorders (ASD) have trouble integrating simultaneous information from their eyes and their ears,” which has been compared to by Stephen Camarata, Ph.D., professor of Hearing and Speech Sciences at Vanderbilt as similar to, “watching a foreign movie that was badly dubbed.” This study was recently published by Mark Wallace, Ph.D., director of the Vanderbilt Brain Institute and co-authored by Camarata. Their work is incredibly important in the field of diseases such as Autism. Unlike many other

researchers, Wallace and his team have focused on sensory function. Their experiment involved putting groups of children, both with normal function and with high functioning Autism and putting them through a variety of audiovisual stimuli that included, “simple flashes and beeps, more complex environmental stimuli like a hammer hitting a nail, and speech stimuli.” After these tests were done, the researchers asked the subjects to identify which auditory and which visual stimuli occurred at the same time. These test showed that children with Autism have, an :enlargement in something known as the temporal binding window (TBW),” which means they have trouble associating sights and sounds with specific times.

A second aspect of the study also showed that children have trouble associating visual and auditory stimuli from speech, which may have something to do with their constant covering of their ears. Although the data here is not conclusive, it has lead the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition to add sensory processing as a key problem for those who suffer from Autism. The whole study has opened up a new field of inquiry on Autism studies and has the possibility of leading to new advances with other psychiatric diseases such as schizophrenia.

Amino Acids and Autism

Photo Credit to fotopedia.com

According to a recent study, an amino acid deficiency may be to blame for a rare form of hereditary autism. As stated in the Nature magazine article, genome sequencing in six children with Middle Eastern backgrounds uncovered “mutations in a gene that stops several essential amino acids being depleted” (Callaway). These mutations inactivate the enzyme BCKD-kinase. As we discussed in class, an enzyme increases the rate of a chemical reaction. However, why the lack of this enzyme would cause autism is still unknown.

Joseph Gleeson, a child neurologist who headed the study, suggests that low levels of branched amino acids to the brain, high levels of larger amino acids , or both might be behind autism symptoms.

Mice who also lacked BCKD-kinase exhibited tremors and epileptic seizures common to autism. However, when given dietary supplements of the branched amino acids, the chemical imbalance was treated and their symptoms disappeared.

Supplements given to the autistic children normalized their blood levels of amino acids. The patients’ conditions did not worsen, however, there was no real evidence that symptoms were reduced. Consequently, Gleeson hopes to conduct a clinical trial testing the effectiveness of dietary supplements in mitigating symptoms of autism and further identify children with the gene mutations for BCKD-kinase.

Matthew Anderson states that Gleeson’s study will “encourage other researchers to explore metabolic pathways as causes of autism.”

The amino acid deficiency may only compose a small percentage of all autism cases, but this is still a large step. The results of further study may present us with the “first treatable form of autism” (Gleeson).

Comments welcome!

 

Identical but Not the Same

 

Some Rights Reserved. More Information: http://www.flickr.com/photos/timoni/3390886772/sizes/s/in/photostream/

After studying genetically inherited traits and diseases it could be easy to assume that genes determine everything about us. While it is true that colorblindness is a sex-linked trait – there is certainly more to the story.

Monozygotic “identical” twins are genetically identical, so they should be the same in all ways shouldn’t they?

Why, then, does one twin get early onset Alzheimer’s disease and the other “identical” twin doesn’t? The same is true for height, autism, and cancer. Although, when one twin has a disorder the other is more likely to get the disease also, that is not always the case.

In the January edition of National Geographic, author Peter Miller discusses the newest theories about how genes, environoment and epigenetics affect our life (and the end of it).

Twins offer scientists a unique opportunity to study how genetically identical people differ. Basically, that means scientists can study how things other than genes affect human development and lifespan. Already, scientists have found that a persons height is only 80% determined by genetics because the heights of “identical” twins differ by about .o8 on average. Using IQ tests, scientists have nearly disproved John Locke’s Tabula Rasa or blank slate theory (the idea that children are born with a blank mind that is either stimulated – (and made intelligent) – or not –  (kept unintelligent)). Specifically, scientists studied twins who had been separated at birth and adopted into different families. In this way, scientists have found that intelligence  is about 75% controlled by genetics.

So that leads to the question, what is it besides genes that affects us humans so drastically?

Environment has something to do with our differences. However, that cannot be the whole story. “The Jim Twins” as they are called in the twin science community, were studied in the 1870’s. They were adopted into different families where both boys were named Jim. Then went on to have the same jobs, marry wives of the same name (two Lynda’s first then two Betty’s), enjoy the same hobbies, enjoy the same brand of cigarette and beer, name their sons James Allan and James Alan… the list goes on. These two lived very similar lives, yet they grew up in very different environments. If environment isn’t the only factor in creating difference then what is?

Scientists have recently come to believe that epigenetics plays a significant role in our lives. Epigenetics (site 2) can be seen as the meshing of environment and DNA. In the words of author Peter Miller “If you think of our DNA as an immense piano keyboard and our genes as keys – each key seach key symbolizing a segment of DNA respinsible  for a particulare note or trait, and all the keys combining to make us who we are – then epigenetic prcesses determine when an how each key can be struck changing the tune.”  Environmental changes do have some impact.  When a pregnant mouse is put under stress during the pregnancy it can create changes in the fetus that lead to abnormal behavior as the rodent grows into adulthood.

However, scarily enough, many epigenetic changes appear to occur randomly (thus creating a probelm for the organized nature/nurture theory). Currently work is being done studying DNA methylation, which is known to make the expression of genes weaker or stronger. Specifically, Andrew Feinburg, director of the Center for Epigenetics at Johns Hopkins School of Medicine, is working to find how DNA methylation relates to autism. Currently, he is using scanners and computers to search samples of DNA from autistic twins who have the disease in varying degrees. He is looking to compare how and why

the genes are expressed differently.

In the end, all we know is that there is more to our future than our genes can tell us. Yes, our genes play a huge role in who we are as people – in terms of appearance, character, intelligence and more – but there are some variables that our environment and epigenetics control.

Main Article: Miller, Peter. “A Thing or Two About Twins.” National Geographic. Jan 2012: 38-65. Print.

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