developmental and epileptic encephalopathy 73

Developmental and Epileptic Encephalopathy (DEE): A Complex Neurodevelopmental Disorder

Developmental and epileptic encephalopathy (DEE) is a group of severe neurodevelopmental disorders characterized by early-onset refractory seizures, specific EEG abnormalities, developmental delay or regression, and intellectual disability [13]. DEEs are typically considered pediatric disorders, with most literature defining their phenotype in children.

Key Features:

• Early-onset refractory seizures: Seizures that occur at a young age and are resistant to treatment.
• Specific EEG abnormalities: Unique patterns of brain activity detected by electroencephalography (EEG).
• Developmental delay or regression: Significant slowing or loss of developmental skills, such as language, motor, or cognitive abilities.
• Intellectual disability: A range of cognitive impairments that can vary in severity.

Causes and Associations:

DEEs are often associated with genetic variants [5-10], which can contribute to the development of both epilepsy and developmental encephalopathy. Other factors, such as environmental influences or prenatal exposures, may also play a role in the etiology of DEEs.

Symptoms and Presentation:

The symptoms of DEE can vary widely depending on the specific disorder and individual case. Common features include:

• Seizures: Frequent seizures that can be generalized or focal.
• Developmental delay: Significant slowing or loss of developmental skills.
• Intellectual disability: A range of cognitive impairments.
• Behavioral problems: Emotional, social, or behavioral difficulties.

References:

[1] Developmental and epileptic encephalopathy 1 (DEE1) is a seizure disorder characterized by a type of seizure known as infantile spasms. Explore symptoms, inheritance, genetics of this condition. [7] [13] Developmental and epileptic encephalopathies (DEEs) are a heterogeneous group of several rare neurodevelopmental disorders characterized by early-onset refractory seizures, specific EEG abnormalities, developmental delay or regression, and intellectual disability (ID).

Developmental and Epileptic Encephalopathy (DEE) is a severe epilepsy syndrome characterized by both seizures and significant developmental delay or regression. The signs and symptoms of DEE can vary greatly depending on the specific syndrome, but some common features include:

• Seizures: Frequent seizures of multiple different types are a hallmark of DEE. These seizures can be resistant to medication and may be accompanied by other symptoms such as loss of consciousness, muscle stiffness, or convulsions.
• Developmental delay or regression: Children with DEE often experience significant delays in their developmental milestones, such as sitting, standing, walking, or talking. In some cases, they may even experience a regression of previously acquired skills.
• Intellectual disability: Many individuals with DEE have intellectual disabilities that range from mild to severe.
• Reduced muscle tone (hypotonia): Some children with DEE may have reduced muscle tone, which can lead to difficulties with movement and balance.
• Hypsarrhythmia: An irregular pattern seen on EEG is a common feature of DEE.
• Dyskinesia: Involuntary movements of the body are also associated with DEE.

It's worth noting that the specific signs and symptoms of DEE can vary depending on the underlying cause, such as genetic variants or other medical conditions. Early diagnosis and treatment are crucial to managing the condition and improving outcomes.

References:

• [1] Developmental and Epileptic Encephalopathies (DEEs) are a group of rare and severe epilepsies. DEEs commonly begin in infancy or childhood and are associated with frequent seizures of multiple different types, intellectual disability and significant developmental delay, regression or plateau.
• [3] Symptoms of epileptic encephalopathy vary greatly depending on the syndrome. However, several epileptic encephalopathy syndromes share symptoms, including: ... Developmental and epileptic ...
• [6] Clinical features · Absent speech · Bilateral tonic-clonic seizure · Cerebral atrophy · Cerebral hypomyelination · Choreoathetosis · Delayed CNS myelination ...
• [10] These conditions are referred to as Developmental Epileptic Encephalopathies (DEE) to acknowledge the presence of multiple causes for the developmental damages. ... Symptoms of epileptic encephalopathy are largely dependent on the specific epileptic syndrome experienced. However, seizures associated with epileptic encephalopathy are typically ...
• [12] Other signs and symptoms may include intellectual disability, reduced muscle tone (hypotonia), hypsarrhythmia (an irregular pattern seen on EEG), dyskinesia (involuntary movement of the body), and spastic di- or quadriplegia. ...

Diagnostic Tests for Developmental and Epileptic Encephalopathy

Developmental and epileptic encephalopathy (DEE) is a severe form of epilepsy syndrome associated with developmental impairment. Accurate diagnosis is crucial to develop effective therapeutic strategies. Several diagnostic tests are used to identify the underlying causes of DEE.

• Electroencephalogram (EEG): An EEG is the most important test in diagnosing DEE-SWAS, particularly in infants and young children [4]. It helps detect abnormal electrical activity in the brain.
• Magnetic Resonance Imaging (MRI): MRI scans are used to rule out other conditions that may be causing the seizures and developmental delay. They can also help identify structural abnormalities in the brain [8].
• Chromosomal Microarray Analysis (CMA): CMA is a powerful tool for detecting clinically significant genomic variants, such as microdeletions and duplications, which can contribute to DEE [6].
• Next-Generation Sequencing (NGS): NGS using a panel of up to 500 genes has become the most widely used technique for identifying genetic abnormalities in early-onset DEE [7].
• Genetic Testing: Recent advances in genetic testing technologies have revolutionized the identification of genetic abnormalities in early-onset DEE. Extensive gene panels, exomes, and genomes are currently accessible, leading to higher rates of diagnosis [5].

These diagnostic tests help identify the underlying causes of DEE, which is essential for developing effective therapeutic strategies and improving prognosis.

References: [4] Aug 2, 2022 - The following exams and tests are used:. [6] by YT Chang · 2023 · Cited by 12 — Chromosomal microarray analysis (CMA) is a powerful tool for detecting clinically significant genomic variants, such as microdeletions and ... [7] Aug 27, 2024 — Genetic testing could help identify the precise aetiology.8 The most widely used technique is next-generation sequencing, using a panel of up to ... [5] by YT Chang · 2023 · Cited by 12 — Clinical testing using extensive gene panels, exomes, and genomes is currently accessible and has resulted in higher rates of diagnosis and ...

Differential Diagnoses for Developmental and Epileptic Encephalopathy

Developmental and epileptic encephalopathy (DEE) is a severe form of epilepsy that affects cognitive and behavioral functions. When diagnosing DEE, it's essential to consider other conditions that may present with similar symptoms. Here are some differential diagnoses to consider:

• Early Myoclonic Encephalopathy: This condition is characterized by early onset seizures, developmental delay, and myoclonic jerks. It often presents in the first few months of life.
• West Syndrome: Also known as infantile spasms, this condition is a severe form of epilepsy that affects infants and young children. It's characterized by clusters of brief, muscle-contracting seizures.
• Other Early-Onset Epileptic Encephalopathies: These conditions include genetic disorders such as DEE27, which is an autosomal dominant neurodevelopmental disorder characterized by delayed psychomotor development and intellectual disability.

Key Points to Consider

When differentiating between these conditions, consider the following factors:

• Age of onset: Early myoclonic encephalopathy and West syndrome typically present in infancy, while DEE27 may have a later age of onset.
• Seizure type: The types of seizures and their frequency can help differentiate between these conditions. For example, early myoclonic encephalopathy is characterized by myoclonic jerks, while West syndrome presents with clusters of brief, muscle-contracting seizures.
• Developmental delay: All three conditions are associated with developmental delay, but the severity and nature of the delay can vary.

References

1. [3] - Abnormal Neonatal EEG
2. [6] - Early myoclonic encephalopathy, West syndrome (see these terms) and other early onset epileptic encephalopathies.
3. [4] - DEE27 is an autosomal dominant neurodevelopmental disorder characterized by delayed psychomotor development and intellectual disability of variable severity.

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