What is Genetic Testing
Overview
Genetic tests analyze DNA, which contains instructions for how an individual’s body develops and functions. Human DNA is almost identical from person to person regardless of factors such as gender, race, or ethnicity but some variability is present in each individual.
Many DNA sequence changes, called DNA variants, are common and benign (not harmful). However, some DNA variants may cause an individual to grow or develop differently and may impact health. Genetic tests can identify DNA variants and provide valuable insights into an individual’s health. The results may also provide information that is relevant to the health of family members.
GeneDX. Rapid Genome Testing for Neonatal & Pediatric Patients. PDF Resource. https://www.genedx.com/patient-support/
Detectable Changes
There are many different types of variants that can be identified in an individual’s DNA. These include changes to a single letter (nucleotide), extra or missing pieces of DNA (duplications or deletions), or structural changes (translocations or inversions) where segments of DNA are rearranged. These changes can either be inherited from a parent or arise as new variants (referred to as de novo) in an egg or sperm cell.
Understanding the specific DNA variant and inheritance in complex medical cases may be crucial for confirming a diagnosis, determining treatment options, and predicting health outcomes.
GeneDX. Rapid Genome Testing for Neonatal & Pediatric Patients. PDF Resource. https://www.genedx.com/patient-support/
Who & When to Test
Exome or genome sequencing is recommended as a first-line test for anyone with unexplained epilepsy by the National Society of Genetic Counselors (NSGC), with endorsement from the American Epilepsy Society (AES). For individuals diagnosed with autism, the American Academy of Pediatrics (AAP) also recommends genetic testing
Detailed information is outlined in the AAP’s clinical report, “Genetic Evaluation of the Child With Intellectual Disability or Global Developmental Delay,” published in Pediatrics on June 23, 2025
The National Society of Genetic Counselors (NSGC) has issued a practice guideline, endorsed by the American Epilepsy Society (AES), which recommends genetic testing for any person with unexplained epilepsy, regardless of age at the time of testing or age at the time the seizures began. Specifically, the guideline recommends exome or genome sequencing as the first line test for unexplained epilepsy.
Smith L, Malinowski J, Ceulemans S, et al. Genetic testing and counseling for the unexplained epilepsies: An evidence-based practice guideline of the National Society of Genetic Counselors. J Genet Couns. Apr 2023;32(2):266-280. doi:10.1002/jgc4.1646
Why It Matters Now
Genetic testing for individuals with epilepsy may offer both clinical and personal benefits to patients and their families.
Clinically, genetic test results may lead to changes in an individual’s epilepsy treatment and management, including:
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initiation of precision treatments tailored to a person’s genetic information
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avoidance of contraindicated (could make a condition worse) treatments
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stopping unnecessary treatments and procedures
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providing information about recurrence risks in future pregnancies
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aiding in reproductive planning and allowing for prenatal diagnosis options for future pregnancies
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enabling genetic testing for at-risk family members
Smith L, Malinowski J, Ceulemans S, et al. Genetic testing and counseling for the unexplained epilepsies: An evidence-based practice guideline of the National Society of Genetic Counselors. J Genet Couns. Apr 2023;32(2):266-280. doi:10.1002/jgc4.1646
Smith L, Malinowski J, Ceulemans S, et al. Genetic testing and counseling for the unexplained epilepsies: An evidence-based practice guideline of the National Society of Genetic Counselors. J Genet Couns. Apr 2023;32(2):266-280. doi:10.1002/jgc4.1646
Smith L, Malinowski J, Ceulemans S, et al. Genetic testing and counseling for the unexplained epilepsies: An evidence-based practice guideline of the National Society of Genetic Counselors. J Genet Couns. Apr 2023;32(2):266-280. doi:10.1002/jgc4.1646
Smith L, Malinowski J, Ceulemans S, et al. Genetic testing and counseling for the unexplained epilepsies: An evidence-based practice guideline of the National Society of Genetic Counselors. J Genet Couns. Apr 2023;32(2):266-280. doi:10.1002/jgc4.1646
Smith L, Malinowski J, Ceulemans S, et al. Genetic testing and counseling for the unexplained epilepsies: An evidence-based practice guideline of the National Society of Genetic Counselors. J Genet Couns. Apr 2023;32(2):266-280. doi:10.1002/jgc4.1646
Genetic testing results may also provide important prognostic information which may influence palliative care (improving quality of life) decisions, impact hospitalization rates, enable referrals to specialty or multidisciplinary clinics, and influence research/clinical trial eligibility.
Smith L, Malinowski J, Ceulemans S, et al. Genetic testing and counseling for the unexplained epilepsies: An evidence-based practice guideline of the National Society of Genetic Counselors. J Genet Couns. Apr 2023;32(2):266-280. doi:10.1002/jgc4.1646
Finally, genetic test results may provide personal benefit to individuals and families. These may include :
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​Access to genetic counseling
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Accurate recurrence risk estimation for family members
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Availability of prenatal diagnosis and/or preimplantation genetic diagnosis
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Cascade testing of family members
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An end to the search for an answer (the “diagnostic odyssey”)
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Potential reduction of guilt/blame/shame
Importantly, a specific diagnosis may provide access to support organizations that connect families with the same genetic diagnosis.
Organizations such as the Rare Epilepsy Network (REN) contain a community of hundreds of rare epilepsy organizations which provides opportunities for families to find gene/diagnosis-specific communities and gain information, education, research opportunities, and support.
With epilepsy, there is a saying that “time is brain” and genetic testing results may have a direct effect on an individual’s medical care. A clinical workup for an individual with seizures commonly consists of an in-depth clinical intake and performing EEGs and MRIs. This is often followed by trying a single medicine or combination of anti-seizure medications (ASMs). These standards of care are valuable, but individuals and families should advocate for genetic testing to be included in an early workup. Although genetic testing is endorsed by professional medical societies, genetic testing is not always offered or accessible. See Section on Where to Find Genetic Testing.
Genetic testing early in the clinical workup has been shown to decrease the time to diagnosis, ending the diagnostic odyssey for up to 50% of individuals and families.
Salahi L. DNA Gains: Pediatricians Leverage Fast Genetic Testing for Neurodevelopmental Disorders. Medscape Medical News. Feb 2025. https://www.medscape.com/viewarticle/dna-gains-pediatricians-leverage-fast-genetic-testing-2025a10002px?form=fpf