A screening test for the prediction of Dravet syndrome before one year of age.
OBJECTIVE
Our aim was to develop a screening test to predict Dravet syndrome before the first birthday based on the clinical characteristics of infants and the SCN1A mutation analysis.


METHODS
Ninety-six patients who experienced febrile seizures before the age of one were enrolled. The patients were divided into two groups-the Dravet syndrome group (n = 46) and the non-Dravet syndrome group (n = 50). We compared the clinical characteristics before one year of age of the two groups. We analyzed all coding exons of the SCN1A gene by the direct sequencing method. Scores from 0 to 3 were assigned to each risk factor based on the odds ratio and p-value.


RESULTS
An age of onset of febrile seizure <or= 7 months, a total number of seizures >or= 5, and prolonged seizures lasting more than 10 min. were regarded as significant risk factors for Dravet syndrome. Other factors highly predictive of this syndrome were hemiconvulsions, partial seizures, myoclonic seizures, and hot water-induced seizures. A total clinical score of six or above was the cutoff value indicating a high risk of Dravet syndrome. SCN1A missense and truncated mutations were detected significantly more often in the Dravet syndrome group than in the non-Dravet syndrome group.


CONCLUSIONS
This simple screening test was designed to be used by general pediatricians. It could help to predict Dravet syndrome before one year of age. If the sum of the clinical risk score is >or= 6, then the performance of an SCN1A mutation analysis is recommended.
Hattori
Junri
J
Department of Child Neurology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan.
Ouchida
Mamoru
M
Ono
Junko
J
Miyake
Susumu
S
Maniwa
Satoshi
S
Mimaki
Nobuyoshi
N
Ohtsuka
Yoko
Y
Ohmori
Iori
I
D000293:Adolescent; D000367:Age Factors; D017668:Age of Onset; D000553:Ambulatory Care; D002648:Child; D004252:DNA Mutational Analysis / Q000379:methods*; D004569:Electroencephalography / Q000706:statistics & numerical data; D005260:Female; D020022:Genetic Predisposition to Disease / Q000453:epidemiology / Q000235:genetics; D005820:Genetic Testing / Q000379:methods*; D006801:Humans; D015994:Incidence; D007564:Japan / Q000453:epidemiology; D008297:Male; D020125:Mutation, Missense / Q000235:genetics*; D062550:NAV1.1 Voltage-Gated Sodium Channel; D009419:Nerve Tissue Proteins / Q000235:genetics*; D010372:Pediatrics / Q000379:methods; D011237:Predictive Value of Tests; D011336:Probability; D012372:ROC Curve; D012189:Retrospective Studies; D012307:Risk Factors; D003294:Seizures, Febrile / Q000175:diagnosis* / Q000453:epidemiology / Q000235:genetics; D015222:Sodium Channels / Q000235:genetics*; D013577:Syndrome; D014888:Wechsler Scales
D062550:NAV1.1 Voltage-Gated Sodium Channel; D009419:Nerve Tissue Proteins; C568242:SCN1A protein, human; D015222:Sodium Channels