Dravet syndrome

General Information (adopted from Orphanet):

Synonyms, Signs: EPILEPTIC ENCEPHALOPATHY, EARLY INFANTILE, 6
EIEE6
SMEI
severe myoclonic epilepsy of infancy
Number of Symptoms 21
OrphanetNr: 33069
OMIM Id: 607208
ICD-10: G40.4
UMLs:
MeSH:
MedDRA:
Snomed:

Prevalence, inheritance and age of onset:

Prevalence: No data available.
Inheritance: Autosomal dominant
[Orphanet]
Age of onset: Neonatal
Infancy
[Orphanet]

Disease classification (adopted from Orphanet):

Parent Diseases: Channelopathy with epilepsy
 -Rare genetic disease
 -Rare neurologic disease
Infantile epilepsy syndrome
 -Rare genetic disease
 -Rare neurologic disease

Symptom Information: Sort by abundance 

1
(HPO:0005484) Postnatal microcephaly 32 / 7739
2
(HPO:0100704) Cortical visual impairment 28 / 7739
3
(HPO:0002123) Generalized myoclonic seizures 62 / 7739
4
(HPO:0006813) Hemiclonic seizures 3 / 7739
5
(HPO:0001268) Mental deterioration 88 / 7739
6
(HPO:0002133) Status epilepticus 59 / 7739
7
(HPO:0002384) Focal seizures with impairment of consciousness or awareness 17 / 7739
8
(HPO:0200134) Epileptic encephalopathy 42 / 7739
9
(HPO:0001270) Motor delay 322 / 7739
10
(HPO:0002121) Absence seizures 62 / 7739
11
(HPO:0001251) Ataxia 413 / 7739
12
(HPO:0001263) Global developmental delay 853 / 7739
13
(HPO:0003593) Infantile onset 249 / 7739
14
(HPO:0002059) Cerebral atrophy 171 / 7739
15
(OMIM) EEG may show migrating focal or multifocal origin (in severe cases) 1 / 7739
16
(HPO:0002120) Cerebral cortical atrophy 187 / 7739
17
(OMIM) Generalized clonic or tonic-clonic seizures 1 / 7739
18
(OMIM) Psychomotor delay after second year 1 / 7739
19
(OMIM) EEG may be normal at first 1 / 7739
20
(HPO:0000006) Autosomal dominant inheritance 2518 / 7739
21
(OMIM) EEG later shows generalized spike or polyspike waves and focal spikes 1 / 7739

Associated genes:

ClinVar (via SNiPA)

Gene symbol Variation Clinical significance Reference

Additional Information:

Description: (OMIM) Dravet syndrome, first described by Dravet (1978), is an early-onset epileptic encephalopathy characterized by generalized tonic, clonic, and tonic-clonic seizures that are initially induced by fever and begin during the first year of life. Seizures are usually refractory ...
Clinical Description OMIM Dravet syndrome, previously known as 'severe myoclonic epilepsy of infancy' (SMEI), is an epileptic syndrome characterized by normal development before onset, seizures beginning in the first year of life in the form of generalized or unilateral febrile clonic ...
Molecular genetics OMIM - Mutations in the SCN1A Gene

In 7 patients with Dravet syndrome, Claes et al. (2001) found heterozygous mutations in the SCN1A gene, including 3 deletions and 1 insertion that resulted in premature stop codons, a ...

Population genetics OMIM From an analysis of data on children with seizures from a national database, Hurst (1990) determined that the incidence of SMEI is 1 in 40,000.