Tuesday, June 18, 2024

Is There A Genetic Test For Autism

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Prenatal Screening Tests For Autism Spectrum Disorders

Genetic Testing for Autism Part 2: Types of Genetic Testing

Autism is not very well understood even today. Now Autism is considered to be a complex neurodevelopmental disorder with both brain and body abnormalities / conditions. However, during the last 10-15 years, several patterns have been recognised, which could provide valuable methods to diagnose incidence of autism during prenatal screening in future.

However even today a Prenatal screening test for Autism is not clinically available. However, with the development in the clinical research, several other prenatal screening tests are either available or under development. We will try to capture them here in this article:

What Might The Doctor Recommend For Your Child If You Have A Family Health History Of Autism Spectrum Disorder

Knowing about your family health history of ASD can help your childs doctor better care for your child. The doctor may check your child more closely for early signs of ASD and might refer your child to a specialist for further evaluation. When a child is closely monitored, signs of ASD can sometimes be noticed at 18 months or youngerexternal icon. A reliable diagnosis of ASD is more common around 2 or 3 years of ageexternal icon and usually made by a developmental specialist. If a child is diagnosed at a young age with ASD, treatment is more effective. Also, a diagnosis of ASD is important for tailoring childrens education once they start school. Learn how early intervention leads to better outcomes for children with ASD.

If you are pregnant or planning a pregnancy, your doctor might recommend carrier screening if you have a family health history of a genetic disorder, such as fragile X syndrome.

New Test Improves Diagnosis Of A Common Genetic Cause Of Autism

A new stand-alone test can more precisely diagnose people with a common genetic cause of autism than the current testing regime.

The international study, led by the Murdoch Childrens Research Institute in collaboration with Lineagen, Inc., an innovative diagnostic genetic testing and clinical information services company based in Utah, published in Scientific Reports, describes a trial of a more cost-effective, accurate and timely way to identify those with Fragile X syndrome, one of the most common genetic causes of intellectual disability and autism spectrum disorder.

Fragile X associated costs to raise one affected child have been estimated at more than $2.5 million to the health system.*

Fragile X affects about 1 in 4,000 children with about 90,000 Australians and over one million Americans impacted in some way. A large proportion of these are women who themselves are not affected with Fragile X, but carry a DNA premutation in their FMR1 gene. This premutation predisposes these women to have children with Fragile X.

A major issue with Fragile X is that at a young age the syndrome is not clinically distinct, with an average age of diagnosis in Australia about five years, and, according to the Centers for Disease Control and Prevention, over three 3 years in the US.

The impact of delayed diagnosis is significant and potentially preventable not only to the families but also for our health system, he said.

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Early Detection Early Intervention

It is comforting to believe that ASD prenatal testing is mostly about helping scientists discover more about genetic variations linked to autism, and identifying autism at the earliest opportunity to allow parents to plan ahead. The argument is convincing when you consider studies examining the effect of early autism intervention, especially with regards to brain plasticity . In this study, the authors concluded that early intervention enhancing social attention, should lead to alterations in brain activity.

A prenatal test detecting autism in a fetus could provide parents with enough time to shift expectations, appeal for all the support theyll need, and prepare themselves emotionally and financially. But preparing for a life of care will also bring up the inevitable question for some parents of whether it would be easier not to embark on the journey at all.

Looking at a study about the estimation of people with Down syndrome in Europe, a reduction of 27% was estimated, meaning approximately 417 000 people with Down Syndrome were living in Europebut without elective abortions there may have been an estimated 572 000.

Another review tells us that between 71 and 100% of women decide to terminate a pregnancy with fetal Down syndrome. In countries like Denmark and Iceland the statistics are close to 100%.

Why Is It Important To Know If You Have A Family Health History Of Autism Spectrum Disorder

Why genetic testing for autism cannot offer definitive ...

Having a family health history of ASD makes you more likely to have a child with ASD, or to have ASD yourself. If you have a child with ASD, you are more likely to have another child with ASDexternal icon, especially if you have a daughter with ASD or more than one child with ASDexternal icon. Your other family members would also be more likely to have a child with ASD.

If you are pregnant or planning a pregnancy, tell your doctor if you or your partner have a family health history of ASD. This information can help your doctor determine how likely you are to have a child with ASD.

When collecting family health history information,

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Is Autism Genetic Or Hereditary

Genetic studies have found genetic heritability to be strongest in monozygotic twins as compared to dizygotic 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, its been proven theres 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 havent 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 , chromosomal duplication , and PTEN gene mutations .

Genetic Tests Offer New Clues To Autism

A pair of genetic tests could help parents and doctors better understand the numerous challenges that a child newly diagnosed with autism might face throughout life, a new study suggests.

The tests tracked down genes that could explain the nature of a child’s autism susceptibility in nearly 16 percent of cases, according to findings published Sept. 1 in the Journal of the American Medical Association.

That number increased to almost 38 percent when researchers used the cutting-edge tests to assess children with certain physical abnormalities. These birth defects are an indication that those children had suffered developmental problems stretching back to the womb, said senior study author Dr. Bridget Fernandez, chair of genetic medicine at Memorial University of Newfoundland in Canada.

Fernandez and her colleagues anticipate that genetic testing of children with autism will continue to increase. She and some other experts believe that, based on the study results, doctors should encourage these tests for kids who show physical signs of developmental problems.

Doctors may be better able to care for children with autism using these tests, because they will have a basic genetic understanding of the kid’s condition, Fernandez said.

For example, the genes linked to a child’s autism might predispose them to obesity or diabetes.

“With that knowledge, now you can start to plan for, prescribe for and treat for those health issues,” Pletcher added.

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Why Genetic Testing Matters

There are different reasons that parents consider genetic testing for their child. Most parents are hoping to find an explanation for why their child has autism. Genetic testing may also:

  • Provide information about prognosis .
  • Lead to changes in the childs medical care and future treatment options, or participation in clinical trials.
  • Provide a diagnosis that may help secure funding for services such as medical therapies or school programs.
  • Help families understand the chance that autism could happen again in a future child.
  • End the search for a cause, eliminating the need for further genetic testing.
  • Empower and connect families.

Your health care providers recommendations for genetic testing will depend on your childs physical traits and behaviors as well as what testing has already been performed. Typically, those recommendations include testing for chromosome disorders and testing for fragile X syndrome. Sometimes a health care provider may order whole exome sequencing , which examines a persons DNA to look for genetic changes associated with ASD.

What Causes Autism Spectrum Disorder

Genetic Testing for Autism Part 3: Diagnosing Autism

Although the cause of ASD is known in some people and not known in others, genetics, biology, and environment are all important factors. Having older parents, a difficult birth, or infections during pregnancy are all examples of factors that might increase the risk for having ASDexternal icon. Beyond these factors, certain people are at higher risk than others. For example, ASD is four times more common in males than femalesexternal icon. People with certain genetic disordersexternal icon, such as fragile X syndrome, tuberous sclerosisexternal icon, and Down syndrome, are more likely to have ASD.

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What Can My Patient Expect At A Genetic Consultation For Autism Spectrum Disorder

The role of a clinical geneticist is to identify the etiology of the ASD where possible, with the hope of improving management of the individual and providing genetic counselling for the family9. A clinical genetics consultation includes a review of the patients prenatal, perinatal, medical and family histories, and a physical examination to document growth parameters and look for evidence of dysmorphic features1.

The Canadian College of Medical Geneticists recommends that chromosomal microarray and fragile X syndrome testing be the first tier laboratory investigation for any male or female whose ASD and/or other developmental disability is unexplained after a thorough history and physical examination10. Second tier investigations may be guided by presentation. Clinical geneticists may ofter genetic testing for a single gene syndrome or a next-generation sequencing panel which could include tens to thousands of genes.

How Is Asd Diagnosed

Diagnosis of ASD is based on clinical criteria, the most recent of which are found in the Diagnostic and Statistical Manual of Mental Disorders Fifth Edition . A child may first be brought to attention following routine screening using a tool such as the validated Modified Checklist for Autism in Toddlers-Revised .

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What Is Genetic Testing For Autism

We know that autism has a strong genetic component. Among individuals with autism, up to 30 percent will have a genetic abnormality. When there are other accompanying diagnoses such as intellectual disability or seizures, the percentage may be higher. However, the genetic abnormalities vary among individuals, meaning the same abnormality may account for only one or two percent of cases.

Its important to note that autism is a clinical diagnosis, based on the observations by the doctors during an office visit, or with additional psychological testing, such as the Autism Diagnostic Observation Schedule . That means that genetic testing is not used to diagnose autism it is recommended after a diagnosis of autism is made and may uncover potential causes.

There are many genetic tests. For autism, there are two that are recommended by a number of respected medical societies, including the American Academy of Child and Adolescent Psychiatry, the American Academy of Pediatrics, the American College of Medical Genetics and the American Society of Human Genetics jointly. The first is chromosomal microarray testing, which looks for missing or extra pieces of genetic material. The second is Fragile X testing, for finding changes in a specific gene called FMRP.

What Are The Benefits Of Genetic Consultation

Genetic testing for autism, explained

Advances in genomic technology have provided the opportunity for many families to receive an answer to the question why does my child have ASD. A genetic diagnosis can potentially lead to guideline-based surveillance and management, tailored treatment options, opportunities to participate in clinical trials, information regarding natural history and prognosis, familial testing and more accurate recurrence risk counselling. In the absence of an identifiable genetic etiology, a recurrence risk range can be quoted based on empirical studies. For families where one child has ASD, the RR is about 10-19%5,6. Males are at higher risk than females. Couples with two children with ASD have a higher RR, around 30%3. The more distant an affected relative is, the lower the RR.

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What Does This Test Tell Me

A CNV is when a region of the chromosome is found to have either less than or more than two copies. On occasion, an individual may have an extra copy or a missing copy of an entire chromosome. More often, the extra piece or missing piece involves a small region or a chromosome, and not the entire chromosome. When this is the case, it is referred to as a copy number variant .

Genetic Testing For Autism

This Got Questions? answer is by geneticist Dean Hartley, Autism Speaks Senior Director of Discovery and Translational Science.

We recommend anyone with an autism diagnosis get genetic testing. Unfortunately, less than half of people with autism do.

Current genetic testing will not give answers to everyone, but without testing we will not be able to give information to some individuals or families that could explain the possible cause of autism and possible future medical conditions.

When you are ready to have genetic testing, we suggest you start with the provider who diagnosed you or your child with autism. That person should be able to refer you to a neurodevelopmental pediatrician, a medical geneticist, or a clinic that specializes in autism or developmental disorders and has experience in genetic testing. We do not recommend directly seeking a company to do genetic testing. A medical specialist or genetic counselor is best qualified to help you understand beforehand what the test will or will not provide and the interpretation of your results.

Once you see this specialist, you will likely be offered the current standard of genetic testing, called microarray testing. Of those who do, 3 to 10 percent will find a genetic variation that likely accounts for a persons autism. One reason for these small percentages is the limitations of microarray technology it only covers a small amount of our 6 billion letters of our DNA that we get from our parents.

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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 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 mothers previous pregnancies led to an infant with a genetic disorder. Genetic screening can diagnose disorders such as cystic fibrosis, chromosome abnormalities like Downs 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.

What Are The Contributing Factors To Autism

Genetic Testing for Autism

Some deem it offensive to speak of high risk factors when it comes to autism. Many autistic adults express pride in who they are despite difficulties of living in a neurotypical world, they celebrate their unique talents and differently wired brains. These are mostly high functioning individuals who are successful, with fulfilling lives. Perhaps referring to factors that may contribute to an individual being diagnosed with autism, or factors raising probability are more appropriate terms to use.

So what raises the probability of having an autistic child? Despite years of research, a specific cause of autism has not been determined and there is much debate. Instead research suggests that a number of influences may elevate the chance that an individual may be on the spectrum. These influences include mostly genetic but also environmental factors.

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A Variety Of Problems

The genetic defect has widespread consequences in the body, and people with even the trait or carrier status may have a variety of physical, emotional, intellectual and behavioral problems or they may be normal. Early menopause is a common problem for women who are carriers. Also, older carriers can develop tremor and balance problems as they age. All of these problems can vary widely in severity among individuals.

Although many children with fragile X syndrome clearly desire socialization, they are often overwhelmed by stimuli, leading to behaviors typical of autism.

About 80 percent of boys with fragile X syndrome demonstrate intellectual disability, compared to about one third of females. Intellectual abilities range from a normal IQ with subtle learning disabilities to severe intellectual disability. Female carriers who are intellectually normal are often found to share characteristic disturbances, such as difficulty in learning math, and emotional problems such as extreme shyness, anxiety, obsessive worrying and mood swings.

Health problems, related to the variety of underlying physical abnormalities, include frequent sinus and ear infections, a lazy eye, dental problems, and heart murmurs indicative of a floppy heart valve. Seizures are common, but are often outgrown by adulthood.

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