Genetic Testing for Autism: What It Can—and Can’t—Tell You

Genetic testing has become a growing part of autism evaluations, but there’s still a lot of confusion around what it actually does. If you’re a parent looking for clarity, you’re in the right place.

Let’s break it down in a way that feels simple and stress-free.

Understanding Genetic Testing in Autism

Genetics play a big role in autism. In fact, researchers believe that most cases of autism have a genetic component. This doesn’t mean anyone is “to blame.” It simply means certain genes can influence how a child’s brain develops.

Genetic testing looks for changes in a person’s DNA that may be related to autism or developmental delays. These tests can’t tell you if a child will have autism, and they don’t measure behavior. Instead, they provide clues about what might be happening biologically.

Why families consider genetic testing

Parents often choose to get testing because:

• They want to understand why their child has autism
• Their pediatrician or developmental specialist recommended it
• Their child also has speech delays, intellectual disability, seizures, or medical concerns
• They are planning future pregnancies and want more information

What genetic testing can reveal

Genetic testing can detect:

• Known genetic syndromes linked to autism (like Fragile X Syndrome)
• Chromosomal microdeletions or duplications
• Single-gene mutations that affect development

Sometimes testing finds something clear and actionable. Other times, results are “inconclusive,” meaning a variation was found but doctors aren’t sure what it means yet. Even then, it can still help guide future monitoring or care.

Types of Genetic Tests Used in Autism Evaluations

Before you ever meet with a genetic counselor, it helps to know the most common testing options. Doctors typically recommend one or more of the following:

Chromosomal Microarray (CMA)

This is usually the first test offered. It looks for small missing or extra pieces of chromosomes. CMA can detect many well-known genetic variations linked to autism.

Fragile X Testing

Fragile X Syndrome is one of the most common inherited causes of autism. A single blood test checks for changes in the FMR1 gene. This test is important for both boys and girls—especially if there’s a family history of developmental delays.

Whole Exome Sequencing (WES)

WES goes deeper. It examines thousands of genes at once, searching for more detailed genetic changes. This test often helps families who haven’t found answers through earlier testing.

Screening for metabolic or medical conditions

Sometimes a doctor may also check for medical issues that can affect development, such as thyroid disorders or metabolic conditions. These aren’t “genetic tests,” but they’re often included as part of a comprehensive evaluation.

What Parents Should Expect During the Process

Genetic testing is usually simple and painless. Most tests use a small blood sample, though some can be done with saliva or a cheek swab.

Meeting with a genetic counselor

A genetic counselor helps you understand:

• What the test looks for
• What the results might mean
• How the findings could impact future medical decisions

They’re also there to support you emotionally. Many parents feel anxious before testing, but counselors do a great job walking you through the process in a calm, reassuring way.

Getting results

Results usually arrive in a few weeks. They will fall into one of three categories:

• Positive: A known genetic change was found
• Negative: No known changes were detected
• Variant of Unknown Significance (VUS): Something unusual was found, but its meaning is unclear

A VUS can feel confusing, but it’s actually very common. Over time, as science learns more, VUS results can be reclassified and become more meaningful.

Does Genetic Testing Change Treatment for Autism?

Genetic testing doesn’t replace autism therapies. It doesn’t predict how a child will behave, communicate, or learn.

However, results can make a difference in other areas, such as:

• Understanding medical risks
• Getting connected to specialists
• Identifying conditions that may require additional care
• Helping families qualify for support services

For some families, just having clear answers brings a sense of relief and direction.

Should Every Child With Autism Get Genetic Testing?

Many professional organizations—like the American Academy of Pediatrics—now recommend offering genetic testing to all children diagnosed with autism or developmental delays.

But it’s always your choice as a parent. Some families want as much information as possible. Others feel it won’t change anything for their child. Both perspectives are completely valid.

If you’re unsure, talking to your child’s pediatrician or a genetic counselor can help you make a decision that feels right for your family.

Conclusion

Genetic testing for autism isn’t about labels or predictions. It’s about understanding. It gives families deeper insight into their child’s development and can open the door to more personalized medical care. While it won’t diagnose autism or change the therapies your child needs, it can offer clarity and peace of mind during a time that often feels overwhelming.

At Milestone Achievements, we’re here to support your child’s journey every step of the way. Whether you’re navigating testing, new evaluations, or starting therapy for the first time, our team is here to help.

If your child needs compassionate, high-quality ABA therapy in Georgia, we’d love to be a part of your family’s support system. Reach out today!

Sources:

• https://www.autismspeaks.org/expert-opinion/genetic-testing-autism
• https://www.brownhealth.org/be-well/genetic-testing-autism
• https://www.bcchr.ca/news/autistic-perspectives-genetic-testing
• https://pmc.ncbi.nlm.nih.gov/articles/PMC4247857/
• https://www.sciencedirect.com/science/article/pii/S1071909120300103

‍