TABLE 1.

Clinical features of 205 patients with SCN1A‐Dravet syndrome

		Percentage	Number of patients	Number of patients with data available
Female		56%	115	205
Characteristics of first seizure
Tonic‐clonic		52%	101	195
Hemiclonic		35%	69	195
Focal impaired awareness		5%	10	195
Myoclonic		4%	7	195
Tonic‐clonic + myoclonic		2%	4	195
Hemiclonic + myoclonic		1%	2	195
Absence		0.5%	1	195
Tonic		0.5%	1	195
Febrile		55%	102	184
Status epilepticus (≥30 min)		34%	56	164
Duration 5 min or shorter		27%	45	164
>1 seizure in 24 h		11%	21	188
Additional seizure types and median age of onset (range)
Tonic‐clonic	6 m (1.6 m−15 y)	96%	191	200
Convulsive status epilepticus	7.5 m (3 m−11.2 y)	89%	178	199
Hemiclonic:	6.1 m (1.5 m−9.8 y)	73%	147	201
Alternating sides		84%	71	84
Always the same side		16%	13	84
Myoclonic	12 m (2.5 m−10 y)	72%	143	200
Focal impaired awareness	18 m (3 m−35.7 y)	72%	142	196
Absence	20 m (6 m−7.6 y)	58%	116	200
Tonic	3 y (3.7 m−25.4 y)	26%	50	190
Nonconvulsive status epilepticus	3.6 y (3 m−25.5 y)	24%	43	178
Atonic	2 y (5 m−7 y)	22%	43	194
Fever sensitive seizures		97%	174	179
Number of different seizure types
One		1.5%	3	205
Two		11%	22	205
Three		19%	38	205
Four		31%	64	205
Five		27%	56	205
Six		9%	19	205
Seven		1.5%	3	205
Developmental characteristics
Normal development before seizures		98%	194	198
Ambulant		99%	185	187
Verbal		97%	184	190
No intellectual disability		1%	1	143
Borderline IQ		6%	8	143
Mild intellectual disability		22%	32	143
Moderate intellectual disability		27%	38	143
Severe intellectual disability		45%	64	143
Autism spectrum disorder		38%	39	103
First epileptiform EEG abnormalities recorded
Generalized spike‐wave		44%	61	139
Focal/multifocal		42%	59	139
Generalized spike‐wave + focal/multifocal		14%	19	139

Abbreviations: EEG, electroencephalography; h, hours; IQ, intelligence quotient; m, months; min, minutes; y, years.