ORPHA:163985
Hyperekplexia-epilepsy syndrome
Publications
161
64.2th percentile
Trials
0
Interventional, condition-specific
Researchers
873
Distinct authors in sample
Gene link
ARHGEF9
Definitive
Readiness
3/6
Stages with a signal
Clinical definition (Orphanet)
A rare, X-linked, syndromic disease characterized by which evolves to and an exaggerated startle response (to sudden visual, auditory or tactile stimuli), followed by the development of early-onset, frequently refractory, tonic or myoclonic . epileptic , , and psychomotor development arrest, with subsequent decline, may be additionally associated.
How rare: <1 / 1 000 000 — fewer than one in a million. In a city the size of Kolkata, that might mean on the order of fifteen people.
Cross-references
Joined from Mondo / Orphanet. MeSH labels may enter searches; UMLS / OMIM / NCIT are stored for reference.
- MONDO:0010375
- MeSH:C564474
- OMIM:300607
- UMLS:C1845102
Additional Mondo synonyms (6)
DEE8 · EIEE8 · developmental and epileptic encephalopathy 8 · epileptic encephalopathy, early infantile, 8 · epileptic encephalopathy, early infantile, type 8 · hyperekplexia-epilepsy syndrome
Research stages
Trial readiness signals
Where this condition sits on an open-data research pipeline — not how close a treatment is, and not medical advice. Empty stages often mean “not in these databases under this Mondo ID,” not “impossible.”
3/6 stages with a signal
No specific-condition interventional trial, but broader-category trials exist — discuss eligibility with a clinician.
- Gene identifiedPresent
Definitive — ARHGEF9
- LiteraturePresent
161 matched papers (88 in last 10 years) Source
- Phenotype characterisedNot checked
Not yet enriched from Monarch / HPO
- Animal modelNot checked
Not yet enriched from Monarch / Alliance
- Orphan designationNot checked
FDA/EMA orphan-drug designation not enriched yet
- Interventional trialPartial
None under the specific name; 1 for broader category hyperekplexia
Biology
Genes and phenotypes
Gene–disease validity from GenCC, plus phenotypes and animal models joined from Monarch Initiative via Mondo ID — not a clinical diagnosis aid.
Do we know what causes it?
Yes — we know a specific gene responsible (ARHGEF9).
GenCC classification: Definitive.
Phenotypes (Monarch / HPO)
Not enriched in this build — Monarch phenotype joins were not run for this record.
Animal models (Monarch / Alliance)
Not enriched in this build.
Literature
Is anyone studying this?
161
161 papers have ever been published on this condition (under this name). For scale, breast cancer has over 700,000. Median papers in the last 10 years for a rare disease in this dataset (publications denominator n=5449) is 41.
161 papers since the earliest indexed year in this search — median last-10-year count for a rare disease in this dataset is 41 (publications denominator n=5449).
88 in the last 10 years · medium confidence · 64.2th percentile (publications denominator)
Phrase hits: 160 · MeSH hits: 1
Who's working on it?
873
Distinct author names in 161 sampled papers — named people below.
Who's working on it?
No interventional trial matched this name; these authors publish on it in the sampled literature — a practical starting point for contact.
- 01Okada M5 papers · 2022
Department of Neuropsychiatry, Division of Neuroscience, Graduate School of Medicine, Mie University, Tsu, Japan.
Papers in Europe PMC - 02Hauser WA4 papers · 2014Papers in Europe PMC
- 03Ottman R4 papers · 2014
Department of Neurology, Columbia University, New York, USA.
Papers in Europe PMC - 04Vieira K4 papers · 2026
Department of Cell Biology & Anatomy, New York Medical College, Valhalla, NY 10595, USA.
Papers in Europe PMC - 05Berg AT3 papers · 2021
Department of Biology, Northern Illinois University, DeKalb, IL 60115, USA. atberg@niu.edu
Papers in Europe PMC - 06Chern CR3 papers · 2026
Department of Cell Biology & Anatomy, New York Medical College, Valhalla, NY 10595, USA.
Papers in Europe PMC - 07Hirose S3 papers · 2019
Department of Pediatrics, School of Medicine, Fukuoka University, Fukuoka, Japan. hirose@fukuoka-u.ac.jp
Papers in Europe PMC - 08Lerche H3 papers · 2010
Department of Applied Physiology, University of Ulm, Germany. holger.lerche@medizin.uni-ulm.de
Papers in Europe PMC - 09Striano P3 papers · 2025
Pediatric Neurology and Muscular Diseases Unit, IRCCS Istituto Giannina Gaslini, Genoa, Italy.
Papers in Europe PMC - 10Velíšek L3 papers · 2026
Departments of Cell Biology & Anatomy, Pediatrics, and Neurology, New York Medical College, Valhalla, NY 10595, USA.
Papers in Europe PMC
Clinical research
Is a treatment being tested?
0
interventional trials for this specific condition
No interventional trial testing a treatment matched this specific condition name. 2 observational studies did — shown below because natural-history and cohort work can be an important step toward a trial. 1 trial are registered for hyperekplexia, the broader category — shown separately because they may or may not enrol this specific subtype.
Data as of 27 July 2026
No matched interventional trials. This is true for 73% of diseases in the trials denominator (5114 of 7003). Here are the researchers publishing on it.
medium confidence · 36.5th percentile (trials denominator)
Recruiting interventional trials
From the matched ClinicalTrials.gov set
No interventional trial testing a treatment was found for this specific condition name on ClinicalTrials.gov.
1 interventional trial matched hyperekplexia, the broader category — listed below. Those studies are not counted in the condition-specific total.
Broader category: hyperekplexia
1
Interventional trials for the parent category, exclusive of NCT IDs already counted above. Eligibility for this subtype is not guaranteed.
Worth raising with a clinician. How we count trials.
Observational and natural-history studies
2 observational studies match this condition. These do not test a treatment and are not counted in the interventional-trial headline, but they are genuine research: natural-history work often defines the endpoints needed for a future rare-disease trial, and families may be able to enroll.
Recruiting or not-yet-recruiting
- NCT01238250·RECRUITING·Online Study of People Who Have Genetic Changes and Features of Autism: Simons Searchlight
Conditions: 16P11.2 Deletion Syndrome · 16p11.2 Duplications · 1Q21.1 Deletion · 1Q21.1 Microduplication Syndrome (Disorder)·Matched via recall expansion
Where to find support
We do not yet link condition-specific patient organisations. These umbrella groups support undiagnosed and ultra-rare families:
India — NPRD
Last verified 2026-07-26This ORPHAcode is not on our curated NPRD list (direct or Mondo-parent match). That does not decide clinical eligibility; families in India should ask a notified Centre of Excellence about current coverage.
Hand-curated for this project. ORPHAcode mappings are best-effort and may be incomplete or imprecise for umbrella categories. Parent (Mondo) matches mean the policy lists a broader category — confirm eligibility with a Centre of Excellence. Financial entitlements summarised from public policy statements and may change. This is not official government guidance.
How we counted this
Europe PMC query (preferred label + any corrected label + Orphanet and Mondo exact synonyms, stoplisted; unioned with resolved MeSH labels when available). UMLS / OMIM / NCIT cross-references are stored on the overview but are not added to the query string.
"Hyperekplexia-epilepsy syndrome" OR "EIEE8" OR "developmental and epileptic encephalopathy 8" OR "epileptic encephalopathy, early infantile, 8" OR "epileptic encephalopathy, early infantile, type 8"
MeSH descriptor terms unioned into the query: Hyperekplexia and Epilepsy
ClinicalTrials.gov query (quoted phrases + MeSH via query.cond, plus recall-expansion terms when used):
"Hyperekplexia-epilepsy syndrome" OR "EIEE8" OR "developmental and epileptic encephalopathy 8" OR "epileptic encephalopathy, early infantile, 8" OR "epileptic encephalopathy, early infantile, type 8" OR "Hyperekplexia and Epilepsy" OR "ARHGEF9" OR "X-linked intellectual disability-epilepsy syndrome" OR "hereditary hyperekplexia"
Recall-expansion terms: ARHGEF9, X-linked intellectual disability-epilepsy syndrome, hereditary hyperekplexia
Study-type breakdown: 0 interventional · 2 observational · 0 expanded access. Only interventional studies enter the trial headline.
Parent-category trials query:
"hyperekplexia"
Query health: ok — strategies attempted: phrase, mesh, recall-expansion; with hits: phrase, mesh, recall-expansion
Run this search on ClinicalTrials.gov
Synonyms dropped by stoplist: DEE8
Confidence reasoning
- Preferred label is multi-word and distinctive
- 1 synonym(s) dropped by stoplist (may under-count)
- No label/synonym collisions with other diseases in this corpus
Ingested 2026-07-27T08:16:12.955Z