Genetic Testing for Autism: What Parents Should Know

Genetic testing for autism looks for a genetic change that may explain why a child is autistic. It does not diagnose autism, which is based on development and behavior. The American Academy of Pediatrics (AAP) recommends offering testing to every autistic child, usually a chromosomal microarray and fragile X test [1][2]. Exome or genome sequencing finds a cause more often.

What is genetic testing for autism?

Autism is diagnosed by observing a child’s development and behavior, and an accurate diagnosis should come before any genetic investigation [3]. Genetic testing for autism is a separate step. It looks at a child’s DNA, usually from a blood or saliva sample, for a change that could explain their autism and any related health or developmental needs.

Most autistic children do not have one specific genetic or medical condition that explains their autism [4]. Genes still play a large part, but usually through many small genetic differences that current clinical tests cannot read as a single answer. To understand the bigger picture, see our guide to what causes autism.

Types of genetic testing for autism

Chromosomal microarray (CMA)

A microarray looks for small missing or extra pieces of chromosomes, called copy number variants. The AAP recommends microarray for all children with autism [1][2]. Earlier studies found microarray identified a cause in roughly 15% to 20% of people with neurodevelopmental conditions [5].

Fragile X testing

Fragile X syndrome is an inherited condition caused by a repeated stretch of DNA in one gene. The AAP recommends fragile X testing for all autistic children [1][2]. A positive result is uncommon but is important for family counseling [2]. Some sequencing tests do not pick up fragile X, so it is often tested separately. In England, NHS genome sequencing now checks for it, so ask which tests are included [6].

Exome and genome sequencing

Exome sequencing reads the parts of genes that make proteins. Genome sequencing reads almost all of a person’s DNA. Testing is often done as a “trio,” using samples from the child and both parents, and NHS labs in England use this approach where possible [7].

In 2019, a consensus statement from genetics and developmental experts, based on a meta-analysis, found that exome sequencing identified a cause in 36% of people with neurodevelopmental conditions overall, including autism. It recommended exome sequencing as a first-tier test [5]. In 2021, the American College of Medical Genetics and Genomics (ACMG) strongly recommended exome or genome sequencing as a first- or second-tier test for children with developmental delay, intellectual disability, or congenital anomalies [8]. The AAP’s 2020 report says exome sequencing can be considered if other testing is negative [2].

Targeted tests

If a child’s features suggest a specific condition, such as tuberous sclerosis or Rett syndrome, doctors may order a targeted test for it [2].

Who is offered genetic testing for autism?

In the US, AAP guidance recommends offering genetic testing to all autistic children, not only those with other medical concerns [1]. In practice, testing is often not done. A study of more than 241,000 children on Medicaid from 2008 to 2016 found low testing rates. Even among children with both autism and intellectual disability, only about 26% had a genetic test [9].

In England, NHS genetic testing depends on a child’s features. Since April 2026, microarray is no longer a routine first test there; genome sequencing is used instead, and microarray only when a specific chromosome condition is suspected [7]. NHS England guidance says testing should be considered when autism is unexplained, especially alongside moderate to profound intellectual disability, seizures, unusual growth or head size, distinctive facial features, or a family history of learning disability [6].

From April 2026, genome sequencing in the national test directory is offered to children with unexplained moderate to profound developmental delay or intellectual disability, or with congenital malformations. Children with isolated neurodiversity, or mild delay with no other features, are not eligible [7]. Fragile X testing should be considered early [6].

How often does genetic testing find a cause?

The answer depends a lot on the child:

• In a meta-analysis of clinical sequencing studies, a genetic diagnosis was found in about 17% of autistic people tested, in highly selected groups [10].
• For neurodevelopmental conditions overall, exome sequencing found a cause in 31% of people with an isolated condition and 53% of those with additional medical features [5].
• In the SPARK research study of 21,532 autistic people, about 8.6% had a clear genetic finding that could be shared with them. Nearly 90% of these were new to the families. Findings were more likely in people with cognitive or complex medical features, and in girls and women [11].

Put simply, most autistic children will not get a genetic diagnosis, but a meaningful number will, especially those with intellectual disability or other health conditions.

Benefits and limits of genetic testing for autism

Possible benefits

The ACMG found that exome or genome sequencing can help with day-to-day and long-term medical care, and with family and reproductive decisions, with relatively few harms [8]. A genetic answer may:

• Explain why your child is autistic and end a long search for answers.
• Point to health checks or specialist care your child may need, depending on the condition found [8].
• Help you understand the chance of autism or a genetic condition in future children. In families with one autistic child, about 1 in 5 younger siblings are autistic by age 3 [12].
• Connect you with families and organizations for the same condition.

Limits

• A negative result does not rule out a genetic cause. The test may not detect every change [13].
• Some results are uncertain. A “variant of uncertain significance” is a DNA change whose effect is not yet known [13]. It should not be treated as a diagnosis.
• A result does not replace support. Whatever the result, your child’s therapy, education, and family support are still based on their own strengths and needs.
• Results can matter for relatives too, because genetic information is shared in families. A genetic counselor can help you think this through [14].

Genetic counseling, results, and privacy

Genetic counseling

Genetic counselors have specialist training. They review family history, explain testing options, help you decide whether testing is right for you, and help you understand results and next steps, including the emotional side [14]. Clinical geneticists also help explain causes and support ongoing care [3]. Ask your doctor for a referral before or after testing.

Understanding results

Results are usually described as positive (a change linked to a health or developmental condition was found), negative (no such change was found), or uncertain [13]. Ask your care team what the result means for your child’s health, for siblings, and for any future pregnancies.

Privacy and insurance

In the US, the Genetic Information Nondiscrimination Act (GINA) stops health insurers and most employers (those with 15 or more staff) from using genetic information in coverage and job decisions. GINA does not cover life, disability or long-term care insurance [15]. If you have concerns, talk to a genetic counselor before testing.

In the US, coverage for genetic testing varies by plan, so ask your doctor’s office to check insurance approval before testing. In England, NHS genomic testing is offered when a child meets the national eligibility criteria, and arrangements may differ in other UK nations [7].

When to talk to a professional

Ask your child’s pediatrician or developmental specialist about genetic testing for autism soon after diagnosis, especially if your child also has intellectual disability, seizures, unusual growth, or other health conditions. Talk to a genetic counselor if you are planning another pregnancy or have questions about family history. For more on next steps, see after an autism diagnosis and questions to ask at an autism assessment.

Frequently asked questions

Can a genetic test tell if my child is autistic?

No. Autism is diagnosed by experienced clinicians who look at a child’s development, communication, and behavior. Genetic testing for autism is done after a diagnosis to look for an underlying cause. Most autistic children do not have a single genetic change that explains their autism, and a normal genetic test does not mean a child is not autistic.

What genetic tests are recommended for autism?

The AAP recommends offering a chromosomal microarray and fragile X testing to all autistic children, with exome sequencing considered if those are negative. Genetics groups now recommend exome or genome sequencing earlier for many children with developmental delay or intellectual disability. Your doctor or a genetic counselor will suggest which tests suit your child.

How likely is genetic testing to find a cause?

It depends on the child. Studies of autistic people have found a genetic diagnosis in roughly 9% to 17% of those tested, and higher rates in children with intellectual disability or other medical features. For neurodevelopmental conditions overall, exome sequencing finds a cause in about one third of people. Many families receive no clear answer.

Is genetic testing for autism covered by insurance or the NHS?

In the US, coverage depends on your plan, so ask your doctor’s office to check approval first. In England, the NHS offers testing to children who meet set criteria, such as autism with moderate to profound intellectual disability, seizures, or other features. Children with autism alone and no other features are not usually eligible.

References

1. Hyman SL, Levy SE, Myers SM; Council on Children With Disabilities, Section on Developmental and Behavioral Pediatrics. Identification, Evaluation, and Management of Children With Autism Spectrum Disorder. Pediatrics. 2020;145(1):e20193447. Link
2. Sanchack KE. Autism Spectrum Disorder: Updated Guidelines from the American Academy of Pediatrics. Am Fam Physician. 2020;102(9):629-631. Link
3. Schaefer GB, Mendelsohn NJ; Professional Practice and Guidelines Committee. Clinical genetics evaluation in identifying the etiology of autism spectrum disorders: 2013 guideline revisions. Genet Med. 2013;15(5):399-407. Link
4. American Academy of Pediatrics Council on Children With Disabilities Autism Subcommittee. Understanding Autism: Information for Families. HealthyChildren.org. Last updated February 20, 2026. Link
5. Srivastava S, Love-Nichols JA, Dies KA, Ledbetter DH, Martin CL, Chung WK, et al. Meta-analysis and multidisciplinary consensus statement: exome sequencing is a first-tier clinical diagnostic test for individuals with neurodevelopmental disorders. Genet Med. 2019;21(11):2413-2421. Link
6. Genomics Education Programme, NHS England. GeNotes: Presentation: Child with suspected autism spectrum disorder. Last reviewed November 21, 2025. Link
7. Leeds Teaching Hospitals NHS Trust. Changes to microarray and WGS National Test Directory from 1st April 2026. March 2026. Link
8. Manickam K, McClain MR, Demmer LA, Biswas S, Kearney HM, Malinowski J, et al. Exome and genome sequencing for pediatric patients with congenital anomalies or intellectual disability: an evidence-based clinical guideline of the American College of Medical Genetics and Genomics (ACMG). Genet Med. 2021;23(11):2029-2037. Link
9. Brown TR, Lee WL, Ventimiglia J, Thurm A, Levy T, Yuan V, et al. Medicaid claims from 2008 to 2016 indicate low rates of genetic testing among children with intellectual disability and autism spectrum disorder. Genet Med. 2025;27(8):101451. Link
10. Stefanski A, Calle-López Y, Leu C, Pérez-Palma E, Pestana-Knight E, Lal D. Clinical sequencing yield in epilepsy, autism spectrum disorder, and intellectual disability: A systematic review and meta-analysis. Epilepsia. 2021;62(1):143-151. Link
11. Wright JR, Astrovskaya I, Barns SD, Goler A, Zhou X, Shu C, et al. Return of genetic research results in 21,532 individuals with autism. Genet Med. 2024;26(10):101202. Link
12. Ozonoff S, Young GS, Bradshaw J, Charman T, Chawarska K, Iverson JM, et al. Familial Recurrence of Autism: Updates From the Baby Siblings Research Consortium. Pediatrics. 2024;154(2):e2023065297. Link
13. MedlinePlus Genetics, US National Library of Medicine. What do the results of genetic tests mean? Last updated July 28, 2021. Link
14. Centers for Disease Control and Prevention. Satisfying Popular Curiosity: What Is Genetic Counseling? Genomics and Precision Health Blog. Published December 28, 2018; last modified April 9, 2024. Link
15. National Human Genome Research Institute. Genetic Information Nondiscrimination Act (GINA). Talking Glossary of Genomic and Genetic Terms. Link

Professional review: this guide is waiting for review by a qualified clinician. It was written and checked against the published sources listed above. How we check our guides.

This guide is general education, not medical advice. Always talk to your child’s doctor or care team. Last checked: October 2026.