We hypothesized that over-expression of NaVβ1 would facilitate the function of residual voltage-gated channels and improve the DS phenotype in the Scn1a+/- mouse model of DS.
Common variants in the sodium channel gene, SCN1A, are associated with febrile seizures, and rare pathogenic variants in SCN1A cause the severe developmental and epileptic encephalopathy Dravet syndrome.
The induction of short repeated seizures, at the age of disease onset for Scn1a mouse models (P21), had no effect in WT mice, but transformed the mild/asymptomatic phenotype of Scn1a<sup>RH/+</sup> mice into a severe DS-like phenotype, including frequent spontaneous seizures and cognitive/behavioral deficits.
These findings demonstrate that electrophysiological data from mammalian expression systems can serve as useful disease biomarker when evaluating SCN1A variants, particularly in view of new and emerging treatment options in DS.
Here we describe that a C57BL/6 J knock-in mouse strain carrying a heterozygous, clinically relevant SCN1A mutation (A1783V) presents a full spectrum of DS manifestations.
De novo loss-of-function mutations in SCN1A are the main cause of Dravet syndrome, a catastrophic encephalopathy characterized by recurrent early-life febrile seizures, a number of other afebrile seizure types that are often refractory to treatment, and behavioral abnormalities including social deficits, motor dysfunction, and cognitive impairment.
Identification of a precise genetic etiology can direct physicians to (i) prescribe treatments that correct specific metabolic defects (e.g., the ketogenic diet for GLUT1 deficiency, or pyridoxine for pyridoxine-dependent epilepsies); (ii) avoid antiepileptic drugs (AEDs) that can aggravate the pathogenic defect (e.g., sodium channel blocking drugs in SCN1A-related Dravet syndrome), or (iii) select AEDs that counteract the functional disturbance caused by the gene mutation (e.g., sodium channel blockers for epilepsies due to gain-of-function SCN8A mutations).
We observe elements of this interictal behavioral syndrome in seizure-prone DBA/2J mice and in mice with a pathogenic Scn1a mutation (modeling Dravet syndrome).
SCN1A mutations are associated with a spectrum of seizure-related disorders, ranging from a relatively mild form of febrile seizures to a more severe epileptic encephalopathy known as Dravet syndrome.
Mice with heterozygous deletion of Scn1a (Scn1a<sup>+/-</sup>) model many features of Dravet syndrome, including spontaneous seizures and premature lethality.
Dravet syndrome (DS) is a genetic form of severe epilepsy often associated with mutation of the SCN1A gene encoding the voltage gated sodium channel Nav1.1.
In a mouse model of DS with a loss of function in Scn1a, reticular thalamic cells exhibited abnormally long bursts of firing caused by the downregulation of calcium-activated potassium SK channels.
Dravet syndrome (DS) is a disease that is primarily caused by the inactivation of the SCN1A-encoded voltage-gated sodium channel alpha subunit (Nav1.1).
Dravet syndrome (DS) is an early onset refractory epilepsy typically caused by de novo heterozygous variants in SCN1A encoding the α-subunit of the neuronal sodium channel Na<sub>v</sub>1.1.
Patients with this variant show a well-defined genotype-phenotype correlation and present with developmental and early infantile epileptic encephalopathy that is far more severe than typical SCN1ADravet syndrome.
In this cross-sectional study, we explore disease characteristics in milder SCN1A-related phenotypes and the nature, occurrence, and relationships of SCN1A-related comorbidities in both patients with Dravet and non-Dravet syndromes.
Stiripentol, known to increase GABA<sub>A</sub> receptor activity as well as the metabolites of GABA<sub>A</sub> receptor agonists, is often used in the treatment of an epileptic encephalopathy, Dravet syndrome (DS), which is caused by mutations mainly in SCN1A and in other genes such as GABRG2.