Genetic studies are evolving every day and now play a key part in identifying which genes could be the reason behind disorders and disabilities. Genetic testing is being used more and more in the medical community, but is there a form of genetic testing for autism spectrum disorder (ASD)?
This article should answer this big question while also taking a closer look at genetic testing in general and highlighting some of the controversies.
What is genetic testing?
Genetic testing is a form of medical test used to identify changes in the DNA sequence or chromosomes. It is an effective method to determine if a person (or if prenatal—embryo or fetus) is prone to a certain disease or disorder.
Genetic testing is a complex but effective means of determining the existence of medical conditions which could potentially alter the development of the fetus or infant. Genetic testing can be conducted prenatally and postnatally. There are three forms of a genetic test: the first is prenatal testing, the second is preimplantation genetic diagnosis on embryos produced through IVF, and thirdly, postnatal diagnostic testing.
Genetic screening can be used to test for genetic abnormalities before birth; this is mostly recommended if there are signs of genetic disorders in the paternal or maternal history, or if the mother’s previous pregnancies led to an infant with a genetic disorder. Genetic screening can diagnose disorders such as cystic fibrosis, chromosome abnormalities like Down’s syndrome, sickle cell disease, fragile X syndrome, Tay-Sachs disease, and several more.
Biological scientists have studied genes for several decades and it has become easier to detect some medical conditions very early. This can assist families in making informed parental decisions and choosing the most effective interventions to assist in daily living.
Can you do genetic testing for autism?
Scientists who focus on autism research are increasingly making discoveries to determine whether ASD is a genetic condition (largely because several genetically related conditions can co-occur with autism). This is leading to more investigations into the potential use of genetic testing for diagnosis.
Genetic testing can be offered to individuals who are suspected of being autistic but these tests don’t test for specific autism genes, but rather test syndromic forms of autism such as abnormalities in the chromosomes—there are certain deletions or duplications that occur in the chromosomes found to be related to the expression of autism symptoms (Schaefer, G. B. & Mendelsohn, 2013).
Current genetic testing for autism diagnosis includes chromosomal microarray analysis, G-banded karyotyping, and fragile X testing. According to DeThorne & Ceman, (2018), postnatal testing is the most common form of genetic testing associated with autism spectrum disorders (ASD).
According to Chen, et al. (2013), genetic testing has become a useful tool for people with a history of autism or those showing possible symptoms. Unfortunately, despite the fact, a genetic cause of autism is identified in less than 25% of individuals on the spectrum. Schaefer, G. B. & Mendelsohn (2013) indicates a success rate of 6-15% but this includes the range of autism spectrum disorders i.e. pervasive developmental disorder not otherwise specified (PDD-NOS), atypical autism, and asperger syndrome.
Genetic testing for autism offers potential benefits such as:
- Identifying the possible cause of autism
- Promoting early detection and intervention
- Helping to develop treatment plans that target autism-related medical conditions
- Could also help develop risk evaluation information, leading to counseling and education for parents
- Chen, et al. also discusses how genetic testing for autism can aid decision-making for potential parents looking to make informed reproductive decisions.
This final point has been met with some controversy. According to DeThorne, (2018), this is because it raises ethical, legal, and social issues (which we will discuss later on in this article).
It is important to note genetic testing for ASD has some limitations. Autism is complex due to its symptoms being expressed differently in every individual on the spectrum. Science puts the complexity of autism down to the complicated interaction between genes and the environment. Other challenges include the fact that genetic causes cannot be identified (as yet) in all autistic children.
Is autism genetic or hereditary?
Genetic studies have found genetic heritability to be strongest in monozygotic twins (identical twins) as compared to dizygotic twins (fraternal twins). This finding has helped genetic scientists learn more about our genes, their patterns, and how they transfer across generations
The studies were deemed to be successful because the score of heritability was higher for autistic monozygotic twins in comparison to dizygotic twins. As a result, scientists now understand that autism is the most transferable neurodevelopmental disorder. Through these studies, it’s been proven there’s a known genetic link that can help us increase our knowledge of autism from a genetic perspective.
In addition, autism has several gene variations and, for want of a better term, “risk factors” which also relate to other conditions. This makes it difficult to narrow down the specific gene or gene variants that “cause autism”, as some gene variants impact the same/similar biological pathways.
So, is autism genetic or hereditary? It seems the answer could be both. Although specific autism genes haven’t been identified, twin studies have indicated possible genetic heritability. On the other hand, genetic testing has found some of the causes of autism relate to genetic syndromes such as fragile X syndrome, Rett syndrome, structural chromosomal deletions (some genes being deleted in the chromosome), chromosomal duplication (sections of a chromosome being duplicated), and PTEN gene mutations (Genovese & Butler, 2020).
The controversy of genetic testing
Genetic testing for autism is a controversial topic for advocates of neurodiversity who argue that it increases misconceptions and discrimination. Some advocates within the disability rights community view autism as a natural form of being—a form of neurological diversity (DeThorne & Ceman, 2018).
The notion that autism and other neurological conditions are a form of diversity is referred to as the “neurodiversity paradigm”. This paradigm focuses on the positive aspects of the condition. In the case of autism, for example, positive aspects might include the ability to focus on detail, and a high tolerance for repetition, etc. The argument posed by this paradigm is that society paints a picture of disability through the lens of “neurotypical status” and this leads to discrimination.
Genetic testing is largely criticized according to the neurodiversity paradigm for two key reasons. Firstly, it could aggravate societal discrimination (for example, positive genetic testing for autism could result in higher abortion rates in a similar way to rates rising for Down’s syndrome abortions). Secondly, funding allocated to genetic testing for autism could instead be allocated to improving the quality of life of those with autism and their families (DeThorne & Ceman, 2018).
Other issues often raised around the concept of genetic testing for autism are: genetic discrimination, privacy concerns, the psychological burden on parents and families, and unequal access to genetic services.
The research by Chen, et al. (2013) studies the awareness, perspectives, and experiences of parents of autistic children in relation to genetic testing. Some participants were in favor of genetic testing for autism while almost one-quarter of parents in the study were against it. The concerns of these parents included fears over methods, potential harms, as well as religious and cultural conflicts.
When we consider these perspectives, some questions need to be answered before we (advocates, physicians, therapists, educators, and parents) can offer any genetic testing recommendations. Key questions which come to mind include: should healthcare providers recommend parents accept genetic testing for their children? How can we ensure genetic testing will benefit parents without causing burden or harm? How do we ensure genetic testing does not lead to a risk of losing insurance coverage?
In conclusion
In the grand scheme of things, genetic testing offers its fair share of advantages, particularly for parents who are curious about the reasons behind their child/children’s autism diagnosis. For example, the study by Chen, et al. (2013) identified a parent who was interested in genetic testing to help him understand why he has autistic children; while a mother hoped it would explain why her two of her biological children (who have different fathers) are on the spectrum. For some individuals diagnosed with ASD, genetic tests could help them understand the biological causes of their conditions.
Since insurance coverage is one of the stipulated concerns of genetic tests, increasing awareness about the Genetic Information Nondiscrimination Act (GINA) could help reassure parents who are reluctant to consider genetic testing due to fears of being let down by medical insurance. The GINA act aims at preventing health insurance companies from denying coverage to individuals who have undergone genetic testing
Another benefit is, if genetic tests become more clearly able to diagnose autism across the spectrum, children could be diagnosed as early as prenatally, making it easier for parents to plan for early intentions.
However, the concerns that genetic testing for autism could lead to an increase in abortions, put pressure on parents, and add to autism discrimination are very important and valid. At the end of the day, the choice to accept genetic testing or not is a personal decision. It is important for everyone to share their opinions and to build a community that supports those with different abilities. No one who differs from a neurotypical society should ever be seen as the “other”.
References
Chen, LS., Xu, L., Huang, TY., et al. (2013). Autism genetic testing: a qualitative study of awareness, attitudes, and experiences among parents of children with autism spectrum disorders. Genet Med 15, 274–281, https://doi.org/10.1038/gim.2012.145
DeThorne, L. S., & Ceman, S. (2018). Genetic testing and autism: Tutorial for communication sciences and disorders. Journal of communication disorders, 74, 61–73. https://doi.org/10.1016/j.jcomdis.2018.05.003
Genovese, A., & Butler, M. G. (2020). Clinical Assessment, Genetics, and Treatment Approaches in Autism Spectrum Disorder (ASD). International journal of molecular sciences, 21(13), 4726. https://doi.org/10.3390/ijms21134726
Schaefer, G. B., Mendelsohn, N. J., & Professional Practice and Guidelines Committee (2013). Clinical genetics evaluation in identifying the etiology of autism spectrum disorders: 2013 guideline revisions. Genetics in medicine: official journal of the American College of Medical Genetics, 15(5), 399–407. https://doi.org/10.1038/gim.2013.32
