Epilepsy Excitation-Inhibition Imbalance Module

Module epilepsy_excitation_inhibition_imbalance 11 disorders Pathograph 5

A conserved network-hyperexcitability module representing the final common pathway of the epilepsies: a primary lesion in ion-channel function, synaptic transmission, or inhibitory circuitry shifts the balance of excitation and inhibition toward excitation, producing neuronal hyperexcitability and hypersynchronous firing that generate recurrent seizures. Genetic (channelopathy/synaptopathy), structural, metabolic, and acquired epilepsies differ in the upstream lesion but converge on excitation/inhibition (E/I) imbalance. Individual disorder entries declare conformance via conforms_to on their pathophysiology nodes, substituting the disorder-specific lesion (e.g., SCN1A loss in Dravet syndrome, GABA-receptor variant, mTOR-pathway malformation) while preserving the conserved E/I-imbalance-to-seizure chain.

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Pathophysiology Nodes

5 shared nodes are defined in this module.

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Cell Types

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Biological Processes

Notes

This is a mechanism module, not a specific disease. Disorder entries reference individual nodes via conforms_to (e.g., "epilepsy_excitation_inhibition_imbalance#Neuronal Hyperexcitability and Hypersynchrony"). Conforming nodes should substitute the disorder-specific driver of E/I imbalance: sodium/potassium/calcium channel variants in genetic channelopathies, GABAergic interneuron dysfunction, mTOR-pathway cortical malformations, or acquired network reorganization after injury. The E/I-balance framework is a useful paradigm but is acknowledged in the literature to be an incomplete account of all epilepsy mechanisms.

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Used By Disorder Entries

CPLX1-Related Developmental and Epileptic Encephalopathy via Cortical Hyperexcitability and Seizures → Neuronal Hyperexcitability and Hypersynchrony

DNM1 Encephalopathy via Reduced Neurotransmission and Cortical Hyperexcitability → Neuronal Hyperexcitability and Hypersynchrony

Dravet_syndrome via SCN1A Gene Mutation → Ion Channel and Synaptic Dysfunction , Neuronal Hyperexcitability → Excitation-Inhibition Imbalance

Epilepsy via Neuronal Hyperexcitability → Excitation-Inhibition Imbalance

GLUT1 Deficiency Syndrome via Neuronal Hyperexcitability and Hypersynchrony , Recurrent Pharmacoresistant Seizures → Recurrent Unprovoked Seizures

Infantile Spasms via Developing brain epileptic network hyperexcitability → Excitation-Inhibition Imbalance

SNAP25 Encephalopathy via Cortical Excitation-Inhibition Imbalance and Seizures → Neuronal Hyperexcitability and Hypersynchrony

STX1B-Related Epilepsy via Temperature-Sensitive Cortical Hyperexcitability → Neuronal Hyperexcitability and Hypersynchrony

STXBP1 Encephalopathy via Cortical Excitation-Inhibition Imbalance and Seizures → Neuronal Hyperexcitability and Hypersynchrony

UNC13A-Related Congenital NDD with Epilepsy via Cortical Hyperexcitability → Neuronal Hyperexcitability and Hypersynchrony

UNC13A-Related NDD with Seizures and Movement Disorder via Gain-of-Function Neurotransmission → Ion Channel and Synaptic Dysfunction , Impaired Second Messenger Regulation of Neurotransmission → Ion Channel and Synaptic Dysfunction

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Pathograph

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Pathophysiology

Ion Channel and Synaptic Dysfunction

trigger

The conserved initiating lesion is an abnormality of neuronal ion channels or synaptic transmission that alters the intrinsic and synaptic excitability of neurons. This encompasses voltage-gated channel variants, neurotransmitter receptor defects, and synaptic-protein abnormalities across genetic and acquired epilepsies.

Neuron CL:0000540

Regulation of Membrane Potential GO:0042391 ABNORMAL Chemical Synaptic Transmission GO:0007268 ABNORMAL

Used by disorders

Dravet_syndrome as SCN1A Gene Mutation

UNC13A-Related NDD with Seizures and Movement Disorder as Gain-of-Function Neurotransmission

UNC13A-Related NDD with Seizures and Movement Disorder as Impaired Second Messenger Regulation of Neurotransmission

Downstream

Excitation-Inhibition Imbalance

Excitation-Inhibition Imbalance

amplifier

Channel and synaptic dysfunction shift the balance between excitatory (glutamatergic) and inhibitory (GABAergic) signaling toward net excitation, through increased excitation, decreased inhibition, or both. Loss of GABAergic inhibitory tone is a recurrent contributor across epilepsy syndromes.

GABAergic Neuron CL:0000617

GABA Signaling Pathway GO:0007214 DECREASED

Used by disorders

Dravet_syndrome as Neuronal Hyperexcitability

Epilepsy as Neuronal Hyperexcitability

Infantile Spasms as Developing brain epileptic network hyperexcitability

Downstream

Neuronal Hyperexcitability and Hypersynchrony

Neuronal Hyperexcitability and Hypersynchrony

central effector

Net excitatory bias produces a hyperexcitable neuronal state in which populations of neurons fire excessively and synchronously. This hypersynchrony is the central effector that converts altered excitability into paroxysmal network discharges.

neuron CL:0000540

Action Potential GO:0001508 INCREASED

Used by disorders

CPLX1-Related Developmental and Epileptic Encephalopathy as Cortical Hyperexcitability and Seizures

DNM1 Encephalopathy as Reduced Neurotransmission and Cortical Hyperexcitability

GLUT1 Deficiency Syndrome

SNAP25 Encephalopathy as Cortical Excitation-Inhibition Imbalance and Seizures

STX1B-Related Epilepsy as Temperature-Sensitive Cortical Hyperexcitability

STXBP1 Encephalopathy as Cortical Excitation-Inhibition Imbalance and Seizures

UNC13A-Related Congenital NDD with Epilepsy as Cortical Hyperexcitability

Downstream

Seizure Generation and Epileptogenesis

Seizure Generation and Epileptogenesis

effector

Hypersynchronous discharges manifest as seizures. Over time, seizure-related and lesion-related processes drive epileptogenesis — network reorganization that lowers seizure threshold and renders the brain chronically prone to spontaneous seizures.

neuron CL:0000540

Downstream

Recurrent Unprovoked Seizures

Recurrent Unprovoked Seizures

consequence

The clinical endpoint is the state of recurrent, unprovoked seizures that defines epilepsy. Seizures may continue to evolve over the lifespan as the underlying network continues to reorganize.

neuron CL:0000540

Used by disorders

GLUT1 Deficiency Syndrome as Recurrent Pharmacoresistant Seizures