| domain | key findings/values | suggested ontology identifiers | evidence/source |
|---|---|---|---|
| Disease definition/scope | Early-infantile developmental and epileptic encephalopathy (EIDEE) refers to DEEs with seizure onset by **3 months** of age; modern usage encompasses historical early infantile epileptic encephalopathy / Ohtahara-spectrum terminology and emphasizes combined developmental impairment plus epileptic encephalopathy. | MONDO: **requires registry verification**; MeSH: **requires registry verification**; ICD-10/11: **requires registry verification**; HPO candidate terms: Seizure onset in infancy **HP:0002373** (verify), Developmental regression/delay terms **require verification** | (pqac-00000004, pqac-00000001) |
| Cohort demographics | Prospective EIDEE cohort: **80 children**, male:female **1.5:1**, median seizure onset **28 days** (range **1–90**), mean follow-up **30 months**. | NCIT/phenotype ontology not essential; Age of onset ontology terms **require verification** | (pqac-00000000, pqac-00000001) |
| Etiologic distribution | Confirmed etiology in **66/80 (83%)**: **genetic 50%**, **structural 19%**, **metabolic 14%** (all vitamin-responsive), **unknown 17%**. | MONDO disease grouping **requires verification**; HPO: Abnormality of metabolism / structural brain abnormality terms **require verification** | (pqac-00000001, pqac-00000017) |
| Seizure/EEG phenotype | Common seizure types included **clonic, tonic, myoclonic**; EEG: **burst-suppression 42%**, **multifocal discharges 30%**, **hypsarrhythmia 13%**. | HPO candidates: Burst suppression on EEG **HP:0010849** (verify); Hypsarrhythmia **HP:0002521** (verify); Myoclonic seizure **HP:0002123** (verify); Tonic seizure **HP:0002069** (verify); Clonic seizure **HP:0002266** (verify) | (pqac-00000000) |
| Neurodevelopmental/behavioral phenotype | Genetic/unknown etiologies showed more severe neurodevelopmental burden than vitamin-responsive/structural groups: severe DD/ID **OR 57**, autistic behaviors **OR 37**, tone abnormalities **OR 9**, movement disorder **OR 19**. | HPO candidates: Global developmental delay **HP:0001263** (verify); Intellectual disability **HP:0001249** (verify); Autism **HP:0000717** (verify); Abnormality of muscle tone **HP:0003808** (verify); Movement disorder **HP:0100022** (verify) | (pqac-00000001, pqac-00000002) |
| MRI/metabolic findings | MRI abnormal in **35/80 (44%)**; among abnormal MRIs, **16/35** had malformations and **19/35** nonspecific changes. Metabolic testing diagnostic in **3/41**, all **biotinidase deficiency** in the prospective cohort summary. | UBERON brain **UBERON:0000955**; HPO candidate: Abnormal brain MRI **HP:0012443** (verify); Biotinidase deficiency disease ontology **requires verification** | (pqac-00000000, pqac-00000017) |
| Outcomes/prognosis | At follow-up: **71%** had severe developmental delay/intellectual disability, **60%** remained drug-resistant, **14%** died. Vitamin-responsive etiologies had the best probability of seizure control; only vitamin-responsive etiology had significant positive effect on seizure control (**P=0.02**). | HPO candidates: Drug resistant epilepsy **requires verification**; Severe global developmental delay **requires verification**; Mortality not typically HPO-coded | (pqac-00000000, pqac-00000001) |
| Genetic architecture | DEEs are highly heterogeneous; 2024 review notes **~50%** of DEE patients overall receive a molecular diagnosis, and by 2023 **825 DEE-associated genes** were cataloged among **925 monogenic epilepsy genes**. | HGNC gene symbols as listed; MONDO/GENO mappings **require verification** | (pqac-00000008, pqac-00000009) |
| Major mechanism class: ion channelopathies | Representative early-infantile DEE genes include **SCN1A, SCN2A, SCN3A, SCN8A, KCNQ2, KCNT1, SCN1B, nicotinic receptor genes**. Functional direction matters: **GOF** variants may benefit from inhibitory/channel-blocking strategies; **LOF** variants may require augmentation approaches. | GO: ion transmembrane transport **GO:0034220**; GO: regulation of membrane potential **GO:0042391**; CL terms for excitatory/inhibitory neurons **require verification** | (pqac-00000007, pqac-00000009, pqac-00000011) |
| Representative gene-mechanism examples | **SCN2A GOF** → neonatal-onset epilepsy, often responsive to sodium-channel blockers; **SCN2A LOF** → later-onset generalized seizures/poorer response. **SCN8A GOF** can cause infantile epilepsies/DEE. **KCNT1 GOF** increases current; quinidine has variable benefit. **KCNQ2** is a key early-infantile potassium-channel DEE gene. | HGNC: SCN2A, SCN8A, KCNT1, KCNQ2; GO annotations above; variant mechanism ontology **requires verification** | (pqac-00000007, pqac-00000009) |
| Synaptic/synaptopathy mechanisms | Synaptopathies are a major DEE class; **STXBP1** was the most common single-gene diagnosis in the prospective EIDEE cohort (**5 patients**). DEE mechanisms include disrupted **SNARE machinery**, synaptic scaffolds, and post-synaptic receptor dysfunction. | HGNC: STXBP1; GO: synaptic vesicle exocytosis **GO:0016079**; GO: chemical synaptic transmission **GO:0007268** | (pqac-00000001, pqac-00000004) |
| Other mechanism classes | Additional DEE mechanisms include **mTOR-pathway dysregulation** (e.g., **DEPDC5** negative regulator; second-hit/somatic LOH in focal cortical dysplasia), **ubiquitination/post-translational pathways** (e.g., **UBA5, KLHL20, WWOX**), transporter dysfunction, and transcriptional/epigenetic regulation abnormalities. | GO: TOR signaling **GO:0031929**; GO: protein ubiquitination **GO:0016567**; GO: regulation of transcription **GO:0006355**; CL/UBERON terms **require verification** | (pqac-00000007, pqac-00000008, pqac-00000004) |
| Cell/tissue emphasis | Reviews highlight dysfunction in **cortical/telencephalic parvalbumin-positive inhibitory interneurons** in some sodium-channel DEEs, alongside roles for excitatory neurons and glia. | CL: parvalbumin-positive interneuron **requires verification**; UBERON: cerebral cortex **UBERON:0000956** (verify); GO CC plasma membrane **GO:0005886** | (pqac-00000009, pqac-00000011) |
| Diagnostic workflow | Recommended workup: **video-EEG**, **3T epilepsy-protocol brain MRI**, early blood/urine metabolic testing, CSF studies when indicated, and rapid genomic testing. Genetic strategy commonly starts with **CMA** for CNVs then **NGS/exome**; **genome sequencing** is entering practice. High-depth methods may be needed for mosaicism. | LOINC/NCIT assay codes **require verification**; HPO/UBERON as above | (pqac-00000014, pqac-00000015, pqac-00000016, pqac-00000017) |
| Diagnostic yield data | In the EIDEE cohort, molecular diagnosis in **53/77 (69%)** tested; **NGS yield 51%**, **microarray yield 14%**. A 2024 review cites pathogenic variants identified in ~**50%** of DEE patients overall. Rapid genome sequencing in infants <1 year with seizures found genetic etiology in **46%** with median **37 days** to diagnosis. | CMA/exome/genome ontology identifiers **require verification** | (pqac-00000001, pqac-00000014, pqac-00000018) |
| Treatable mimics / metabolic-vitamins | Early evaluation should prioritize **treatable and vitamin-responsive epilepsies**. Reported empiric trials include **pyridoxine, pyridoxal 5'-phosphate, folinic acid, biotin**; vitamin-responsive etiologies had the most favorable seizure-control outcomes in the prospective cohort. | CHEBI/DrugBank IDs **require verification**; NCIT intervention terms for pyridoxine/biotin/folinic acid **require verification** | (pqac-00000015, pqac-00000017) |
| Genotype-guided pharmacotherapy | Sodium-channel blockers may be effective in selected **GOF** channelopathies; cohort examples with benefit included **SCN1A, KCNQ2, FGF12, SCN8A, SCN2A** (6 patients total). **Quinidine** benefited one **KCNT1** patient in the cohort. | NCIT: Carbamazepine/Phenytoin/Lacosamide/Quinidine **require verification**; CHEBI drug IDs **require verification** | (pqac-00000002, pqac-00000007, pqac-00000015) |
| Important cautions | Precision treatment must consider direction of effect. In **Dravet syndrome / SCN1A LOF**, **carbamazepine/oxcarbazepine** can worsen seizures and should be avoided, whereas sodium-channel blockers may help some **SCN2A/SCN8A/KCNQ2 GOF** cases. | NCIT drug terms **require verification**; disease-specific MONDO IDs **require verification** | (pqac-00000018, pqac-00000007) |
| Diet therapy | **Ketogenic diet** is used for ASM-resistant DEE and was described as an early treatment option in genotype-driven DEE management; one 2024 cohort/review context reported approximately **30% seizure freedom** and **60% >50% seizure reduction** in young patients with EIDEE/related DEEs. | NCIT: Ketogenic Diet **requires verification** | (pqac-00000003, pqac-00000016) |
| Surgery/interventional care | For **unifocal resectable structural lesions** (e.g., focal cortical dysplasia), epilepsy surgery evaluation is recommended and can be transformational. | NCIT: Epilepsy surgery **requires verification**; UBERON lesion-specific anatomy **requires verification** | (pqac-00000014) |
| Supportive/holistic care | Holistic care is necessary because long-term developmental outcomes are often abnormal despite seizure treatment; common needs include management of **motor dysfunction, psychiatric features, speech and sleep problems**, developmental therapies, and family support. | HPO candidates: Sleep disturbance / speech delay / motor delay **require verification**; NCIT rehab/supportive care terms **require verification** | (pqac-00000018) |
| Inheritance/counseling | In the EIDEE cohort’s pathogenic variants, **67% autosomal dominant** and **33% autosomal recessive** inheritance were reported. High-depth sequencing detects parental mosaicism; one review reported mosaicism in **8%** of apparently de novo cases, relevant to recurrence-risk counseling and prenatal/IVF options. | GENO inheritance terms **require verification** | (pqac-00000000, pqac-00000015) |
| Experimental therapies | Emerging precision therapies include **antisense oligonucleotides (ASOs)** and gene-augmentation/activation strategies. Examples from DEE reviews: **STK-001** for SCN1A/Dravet (TANGO strategy), exploratory **SCN2A ASO** approaches, and AAV-mediated gene therapy concepts. | NCIT: Antisense oligonucleotide therapy / Gene therapy **require verification** | (pqac-00000007, pqac-00000012, pqac-00000006) |
| Experimental models | Model systems cited across DEE reviews include **mouse**, **iPSC-derived neurons**, and other preclinical platforms. Dravet/iPSC data show selective impairment of inhibitory neurons; mouse models demonstrated rescue with **AAV-SCN1A**, **CRISPRa/dCas9 activation**, and cell-selective GABAergic targeting. | CL: induced pluripotent stem cell-derived neuron **requires verification**; NCBITaxon mouse **NCBITaxon:10090**; GO/CL interneuron terms **require verification** | (pqac-00000006, pqac-00000009, pqac-00000010) |
| Real-world implementation / trial landscape | Active interventional DEE trials retrieved included **NCT07019922** (elsunersen in pediatric SCN2A-DEE, recruiting), **NCT05737784** (PRAX-222 in early-onset SCN2A-DEE, recruiting), **NCT04639310** / **NCT04912856** (XEN496/ezogabine in KCNQ2-DEE, terminated), **NCT06983158** (CAP-002 gene therapy for STXBP1 encephalopathy, terminated), and broad DEE programs such as **relutrigine NCT07010471** and **LP352 NCT06719141/NCT06908226**. | ClinicalTrials.gov NCT identifiers as listed; NCIT interventions **require verification** | Retrieved clinical trial records in prior tool output; narrative support from (pqac-00000007, pqac-00000012) |


*Table: This table summarizes core disease-definition, cohort, mechanistic, diagnostic, therapeutic, and translational findings for Early-Infantile Developmental and Epileptic Encephalopathy. It is formatted for direct knowledge-base curation and flags ontology identifiers that require external registry verification.*