developmental and epileptic encephalopathy, 8
MONDO:0010375Mondo
Findings
No curated finding names developmental and epileptic encephalopathy, 8 yet. Everything below is reference data from Mondo, HPO and GenCC, not evidence about what affects it.
Definition
- Inheritance
- X-linked recessive inheritance
- Onset and course
- Congenital onset · Infantile onset · Death in childhood · Childhood onset
HPO, annotations 2026-09-02
Features
15 features
What the disease is reported to present with, and how often among people who have it — never how often a feature means the disease. HPO, annotations 2026-09-02.
- Developmental regressionHPOHP:0002376
- 1 of 1 reported patient
- Frequent (30% to 79% of cases)
- Epileptic encephalopathyHPOHP:0200134
- 1 of 1 reported patient
- Frequent (30% to 79% of cases)
- Exaggerated startle responseHPOHP:0002267
- 1 of 1 reported patient
- Frequent (30% to 79% of cases)
- Global developmental delayHPOHP:0001263
- 3 of 3 reported patients
- HypertoniaHPOHP:0001276
- 1 of 1 reported patient
- Frequent (30% to 79% of cases)
- Severe intellectual disabilityHPOHP:0010864
- 1 of 1 reported patient
- Tonic seizureHPOHP:0032792
- 1 of 1 reported patient
- EEG with temporal focal spikesHPOHP:0012018
- Frequent (30% to 79% of cases)
- Focal impaired awareness seizureHPOHP:0002384
- 1 of 2 reported patients
- Frequent (30% to 79% of cases)
- Generalized tonic seizureHPOHP:0010818
- Frequent (30% to 79% of cases)
- Hypoplasia of the frontal lobesHPOHP:0007333
- 1 of 2 reported patients
- Frequent (30% to 79% of cases)
- Bilateral tonic-clonic seizureHPOHP:0002069
- 1 of 2 reported patients
Show the remaining 3
- Frontal polymicrogyriaHPOHP:0006821
- 1 of 2 reported patients
- OvergrowthHPOHP:0001548
- 1 of 2 reported patients
- TrigonocephalyHPOHP:0000243
- 1 of 2 reported patients
- Occasional (5% to 29% of cases)
Genes
1 gene
Germline variants in the gene encoding each protein, as classified by GenCC submitters, each in their own words. Limited, disputed and refuted submissions are listed too.
- ARHGEF9HGNC:14561
- Definitive · Ambry Genetics · X-linked · 2024
- Strong · Labcorp Genetics (formerly Invitae) · X-linked · 2022
- Strong · G2P · X-linked · 2025
- Strong · PanelApp Australia · X-linked · 2025
- Supportive · Orphanet · X-linked · 2021
Where it sits
Other names
6 names
Resolves to: developmental and epileptic encephalopathy, 8
- Also called
- DEE8developmental and epileptic encephalopathy 8EIEE8epileptic encephalopathy, early infantile, 8epileptic encephalopathy, early infantile, type 8hyperekplexia-epilepsy syndrome