These discoveries highlight the importance of genetic testing for autistic children to identify co-occurring conditions.
April 25, 2025 • 5 min read
GeneDx data played an instrumental role in the recent connection of 230 additional genes to autism spectrum disorder (ASD), a discovery that was announced at the 2024 American Society of Human Genetics.1 The findings support the notion that as more genes are associated with ASD, the likelihood of exome and genome sequencing getting to the root cause of autism increases.
That exome and genome sequencing can also identify conditions that commonly co-occur with autism, including epilepsy and intellectual disability, is particularly resonant considering that 74% of patients with autism also experience a co-occurring condition.2 Identifying those conditions early—in some cases, even before symptoms appear—can enable early treatment, inform family planning, and connect families with support groups.
Oliver’s case study is not unusual—and yet, it took his family four years to get a diagnosis that an exome test could have provided in a few weeks.
Oliver started missing milestones and showing signs of intellectual developmental delays at just 15 months, and still had trouble standing and speaking at age two. By that time, his parents had also started to suspect autism based on his poor eye contact and lack of social behavior. Although he received autism, Duane’s syndrome, and myopia diagnoses shortly thereafter, his pediatrician only ordered FMR1 and chromosomal microarray testing—both of which were reported as normal.
Four years after his autism diagnosis, Oliver finally received exome sequencing and the resulting genetic diagnosis: MED13-associated syndrome. If Oliver’s doctor had ordered exome sequencing after his initial presentation of developmental delay—in line with society guidelines—the genetic test would have delivered those results in five weeks. That critical information could have provided his parents with a specific diagnosis, more targeted family planning guidance, and access to community support groups and resources when Oliver was just three years old.
Compared to other genetic testing options for neurodevelopmental disorders, exome testing is more likely to deliver a genetic diagnosis for patients with autism.
Parents of children with undiagnosed conditions like Oliver experience an overwhelming number of challenges. On average, a child with neurodevelopmental disorders:
Waits over 5 years for a diagnosis.10,11
Accrues over $10,000 in additional health costs to the system.11
Undergoes more than 5 tests on their path to a genetic diagnosis.11
In addition to informing treatment and care, a genetic diagnosis can also give parents the peace of mind that comes from understanding the root cause behind their child’s symptoms.
Stories like Oliver’s reiterate why guidelines recommend exome as a first-line test for patients with conditions that often co-occur with ASD. The American College of Medical Genetics and Genomics (ACMG) recommends exome or genome sequencing as a first-tier test for individuals with developmental delay, intellectual disability, and congenital anomalies. Following these guidelines may be the key to identifying a diagnosis sooner for children like Oliver.
*Case study is based on GeneDx patient testing, with all identifying information removed.
References: 1. Satterstrom, Frederick, et al. The largest to-date exome study of autism spectrum disorder triples the number of autism-associated genes. Presented at: American Society of Human Genetics 2024; Nov 8; Denver, CO. 2. Khachadourian V, et al. Transl Psychology 2023 Feb 25;13 (1) :7 3.Arteche-López A, et al. Genes.2021(12):560. 4. Ní Ghrálaigh F, et al. J Autism Dev Disord. 2023 Jan;53(1):484-488. 5. Srivastava S, et al. Genet Med.2019 Nov;21(11):2413–2421. 6. Tammimies K, et al. JAMA.2015 Sep 1;314(9):895-903. 7. Lindy A,et al. Poster Presented at: AAN 2022 Annual Meeting; April 24-26, 2022; Seattle, WA. 8. Harrington JW, Emuren L, Restaino K, et al. Parental Perception and Participation in Genetic Testing Among Children with Autism Spectrum Disorders. Clin Pediatr (Phila) 2018 Dec; 57(14) 1642-1655. Doi: 10/1177/0009922818803398. Epub 2018 Sep 28 9. Zhao S, Chen WJ, Dhar SU et al. Pursuing genetic testing for children with autism spectrum disorders: What do parents think? J Genet Couns 2021 Apr;20 (2): 370-382. Doi 10.1002/igc4.1320. Epub 2020 Sep 28 10. Marwaha S, Knowles JW, and Ashley EA. A guide for the diagnosis of rare and undiagnosed disease: beyond the exome. Genome Med. 2022 Feb 28;14(1):23. 11. Soden SE, Saunders CJ, et al. Sci Transl Med. 2014 Dec 3;6(265):265ra168. doi: 10.1126/scitranslmed.3010076. 12. Savatt JM, Myers SM. Genetic Testing in Neurodevelopmental Disorders. Front Pediatr. 2021;9:526779. doi:10.3389/fped.2021.526779 13. Stafford CF, Sanchez-Lara PA. Impact of Genetic and Genomic Testing on the Clinical Management of Patients with Autism Spectrum Disorder. Genes (Basel). Mar 25 2022;13(4)doi:10.3390/genes13040585
