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PubMed This is a summary of 21 peer-reviewed journal articles Updated
Neurology · Developmental and Epileptic Encephalopathy

Reading the Roadmap: Decoding Your Child's Reports

At a Glance

Genetic and EEG reports provide a critical roadmap for managing developmental and epileptic encephalopathy (DEE). Understanding key terminology like pathogenic mutations, de novo inheritance, and EEG patterns like hypsarrhythmia empowers parents to actively partner in their child's medical care.

Navigating medical reports can feel like learning a foreign language. However, these documents are the roadmap for your child’s care. By understanding the key terms in your child’s genetic report and EEG (electroencephalogram), you can move from being a recipient of information to an active partner in the clinical team [1].

Understanding Your Genetic Report

A genetic report identifies the specific “instruction” in your child’s DNA that is causing the DEE.

Key Genetic Terms

  • Pathogenic / Likely Pathogenic: This means the lab is highly confident that this specific variant is causing the disease [2][3].
  • Variant of Uncertain Significance (VUS): This is a “maybe.” The lab found a change, but there isn’t enough research yet to prove it causes disease [4]. These are often re-evaluated as more data becomes available [5].
  • De Novo: This means the mutation occurred spontaneously in the child and was not inherited from either parent [6].
  • Exome Sequencing (WES): A test that looks at all the “coding” parts of the genes (the exome), which is where most disease-causing mutations are found [2].
  • Genotype (p. and c.): The c. (cDNA) change describes the error at the DNA level, while the p. (protein) change describes how that error changed the actual protein the brain uses [7][8].

The Genetic Completeness Checklist

Ensure your report includes these five critical pieces of data to guide precision medicine:

  1. Gene Name: (e.g., SCN2A, KCNQ2, STXBP1) [9].
  2. Specific Variant: Both the c. and p. notations [7].
  3. Zygosity: Usually “heterozygous,” meaning only one of the two copies of the gene is mutated [10].
  4. Inheritance: Whether it was de novo or inherited from a parent [11].
  5. Pathogenicity: The classification (Pathogenic vs. VUS) according to ACMG guidelines [2].

Deciphering the EEG Report

An EEG measures the brain’s electrical activity. In DEE, the EEG is used not just to find seizures, but to look at the brain’s overall “health” and organization [12].

Common EEG Findings in Plain Language

  • Background Slowing: This refers to the brain’s basic electrical rhythm. If the background is “slow” for the child’s age, it often indicates a higher risk for developmental delay [12][13].
  • Hypsarrhythmia: A very disorganized, high-voltage, chaotic pattern. This is a hallmark of West Syndrome and is often seen with infantile spasms [14][15].
  • Suppression-Burst: A pattern where the EEG goes nearly flat (suppression) followed by a burst of high activity. This is seen in the most severe neonatal DEEs, like Ohtahara Syndrome [16][17].
  • Spike-and-Wave: These are “epileptiform” discharges. The “spike” is the sudden electrical fire, and the “wave” is the brain’s attempt to reset [18].
  • CSWS / ESES: This stands for Continuous Spike-and-Wave during Sleep. This is a pattern that appears almost exclusively when a child is sleeping and can cause significant regression in language and behavior [19][20].

Why the “Interictal” Matters

Most EEGs are “interictal,” meaning they record activity between seizures. Even if your child does not have a seizure during the test, these interictal discharges are critical because they show how much “background noise” the brain is dealing with, which can interfere with learning and development [12][21].

Always ask your doctor how your child’s EEG pattern correlates with their specific genetic finding, as some genes have very predictable EEG “signatures” [9][11].

Return to Home Page

Common questions in this guide

What does a de novo mutation mean on my child's genetic report?
A 'de novo' mutation means the genetic change happened spontaneously in your child and was not inherited from either parent. This is a common finding in many developmental and epileptic encephalopathies.
What should I do if my child's DEE genetic test shows a Variant of Uncertain Significance (VUS)?
A Variant of Uncertain Significance means a genetic change was found, but there isn't enough medical research yet to confirm it causes the disease. You should work with your genetics team to determine when this result should be re-evaluated as new data becomes available.
What does hypsarrhythmia mean on a child's EEG?
Hypsarrhythmia is a highly disorganized, chaotic pattern of electrical activity seen on an EEG. It is a hallmark sign of West Syndrome and is frequently associated with infantile spasms.
Why does the neurologist care about my child's EEG between seizures?
The brain wave activity between seizures, known as interictal activity, shows the overall health and organization of the brain. High levels of background electrical noise can interfere with your child's learning and development, even when they are not actively having a seizure.
What does background slowing mean on an EEG report?
Background slowing indicates that the basic electrical rhythm of the brain is slower than expected for a child's age. This finding often points to a higher risk for developmental delays.

Questions to Ask Your Doctor

Curated prompts to bring to your next appointment.

  1. 1.What is the protein change (p.) and cDNA change (c.) for my child's variant, and what do they tell us about the severity of the mutation?
  2. 2.If this is a Variant of Uncertain Significance (VUS), when should we plan to have it re-evaluated or re-analyzed?
  3. 3.Does my child's EEG show 'hypsarrhythmia' or 'suppression-burst'? What do these patterns mean for their specific syndrome diagnosis?
  4. 4.Does the EEG background activity show 'slowing' for their age, and how much of this is caused by the seizures versus the underlying condition?
  5. 5.Did the EEG capture sleep, and did it show 'Continuous Spike-and-Wave during Sleep' (CSWS)?

Questions For You

Tap a prompt to share your answer — we'll use it plus this page's context to start a tailored conversation.

References

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This guide to interpreting DEE genetic and EEG reports is for educational purposes only. Always consult your child's neurologist or geneticist to understand what your child's specific test results mean for their care.

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