The mechanism modules that upstream epilepsy entries reach on their way to recurrent seizures. Epilepsy is not one mechanism: distinct lesions in inhibitory-interneuron development, presynaptic vesicle release, postsynaptic scaffolding, cortical growth signaling, and repeat-RNA toxicity each drive a different route to the same endpoint, and each has its own treatment logic. The collection groups those upstream lanes together with the shared excitation-inhibition convergence module they feed. Membership records that a module is an evidenced route to seizures or to excitation-inhibition imbalance in at least one curated DisMech entry; it does not claim the lanes are exhaustive or mutually exclusive, and a single disorder commonly conforms to the convergence module plus one lane.
The convergence point rather than a lane: ion-channel or synaptic dysfunction shifts excitation and inhibition toward excitation, producing hypersynchronous firing and recurrent seizures. Every other member feeds this chain, and it carries by far the most conformers in the KB.
The developmental-inhibitory lane: subpallial lineage programs fail, cortical GABAergic interneurons are absent or mislocalized, and the resulting interneuronopathy produces developmental epilepsy.
The presynaptic lane: defects in vesicle docking, priming, calcium-triggered fusion, or endocytosis impair neurotransmitter release. Eight of its ten current conformers are epilepsy or DEE entries: STXBP1, SNAP25, STX1B, SYN1, CPLX1, DNM1, and the two UNC13A entries. The other two are SYT1 (Baker-Gordon syndrome, which carries no seizure phenotype at all) and VAMP2, neurodevelopmental disorders in which seizures are not a defining feature; the module is a member on the strength of the eight.
The postsynaptic lane: loss of a core postsynaptic-density organizer disorganizes the excitatory synapse and perturbs glutamate-receptor localization, an excitation-inhibition imbalance route distinct from the presynaptic one.
The structural lane: constitutive PI3K-AKT-mTOR activation in neural progenitors, frequently post-zygotic, produces the epileptogenic cortical dysplasia that underlies drug-resistant focal epilepsy and is the rationale for mTOR-inhibitor therapy.
The repeat-expansion lane: intronic TTTCA-containing pentanucleotide expansions across unrelated host genes converge on UUUCA repeat RNA toxicity, cerebellocortical dysfunction, and cortical hyperexcitability. Included because it is a mechanistically independent route to seizures, not because it is pediatric; familial adult myoclonus epilepsy is adult-onset.
Furthermore, genetic defects affecting ion currents and cellular osmolarity, cytoskeletal structure and integrity of myelinated axons, neuronal morphology, and purine metabolism have been found to underlie DEE with progressive course.
States the organizing premise of this collection: mechanistically unrelated classes of lesion underlie the epileptic encephalopathies, so the mechanism layer needs several distinct modules rather than one.
This is a navigation and framework record, not a mechanism module or disease grouping, and it is deliberately not a pediatric-only collection: mechanism lanes are shared across ages, and age at onset is a property of the disease entries (see the ILAE 2022 age-at-onset groups used in research/pediatric_epilepsy_census.md). Membership is limited to modules that are an evidenced route to seizures or to excitation-inhibition imbalance in at least one curated entry, which is the rule the description states. It is deliberately not a rule about a module's terminal node: synaptic_vesicle_cycle ends at neurotransmitter release failure and excitatory_synapse_scaffold_disruption continues past excitation-inhibition imbalance to a generic neurodevelopmental terminus, and both are correct members because their epilepsy conformers reach seizures through them. A module may also have conformers outside the epilepsies; that does not disqualify it, and the member descriptions say where that is the case. Four modules that recur in epilepsy entries for other reasons are excluded on purpose, because in their chains seizures are incidental rather than the point: glutamate_excitotoxicity is a route to neuronal death, metabolic_intoxication_decompensation to acute encephalopathy, and epigenetic_machinery_neurodevelopmental_dysregulation and congenital_disorder_of_glycosylation are general neurodevelopmental modules in which seizures are one output among many. Several lanes the KB curates as prose but not yet as modules have no member here; they are enumerated as gaps in docs/reports/pediatric-epilepsy-census-2026-09-10.md.