Epileptic encephalopathies and progressive neurodegeneration

Area of Science:

• Neuroscience
• Genetics
• Pediatric Neurology

Background:

• Developmental encephalopathies (DE), epileptic encephalopathies (EE), and developmental and epileptic encephalopathies (DEE) are overlapping neurodevelopmental disorders.
• These conditions present with early-onset seizures, developmental delay, or regression, stemming from diverse etiologies.
• Historically, progressive vs. nonprogressive courses were distinguished, with DEE progression often linked to severe seizures and EEG abnormalities.

Purpose of the Study:

• To review genetic DEE, highlighting the interplay between neurodevelopmental and neurodegenerative processes.
• To connect genetic findings with the spectrum of clinical and anatomical severity in DEE.
• To illustrate how mutations in the same gene can lead to varied phenotypes, from severe deterioration to milder forms.

Main Methods:

• Review of current literature on genetic DEE.
• Analysis of next-generation sequencing and functional studies.
• Synthesis of findings linking neurodevelopmental and neurodegenerative aspects.

Main Results:

• Next-generation sequencing has identified numerous genetic causes for DEE.
• Functional studies reveal a spectrum of severity, including neurodegeneration, associated with specific gene mutations.
• The same gene mutations can manifest as rapidly progressive or milder phenotypes.

Conclusions:

• Genetic DEE blurs the lines between neurodevelopmental and neurodegenerative disorders.
• Understanding the genetic basis is crucial for characterizing the broad spectrum of DEE severity.
• This perspective offers insights into the mechanisms underlying these complex neurological conditions.