Congenital hyperekplexia: five sporadic cases.
We report fives sporadic cases of hyperekplexia or startle disease characterized by a highly exaggerated startle reflex and tonic attacks. Affected neonates suffer from prolonged periods of stiffness and are at risk for sudden death from apnea. An early diagnosis is needed. Sudden loud sounds, unexpected tactile stimuli or percussion at the base of the nose can also elicit excessive jerking or tonic attack. The diagnosis of hyperekplexia is a purely clinical one. A defect of the alpha1 subunit of inhibitory glycine receptor (GLRA1) has been observed in the dominant form with a mutation in the chromosome 5. Clonazepam is effective and decreases the severity of the symptoms. The disease tends to improve after infancy and the psychomotor development is normal. The major form of "hyperekplexia" should be considered whenever one is confronted with neonatal hypertonicity associated with paroxysmal tonic manifestations (without electroencephalography anomalies).


CONCLUSIONS
the diagnosis of hyperekplexia should be evaluated in any neonate with tonic attacks without evident cause.
Rivera
Serge
S
Service de Réanimation Néonatale, Pédiatrie 2, Hôpitaux Universitaires de Strasbourg, 1 avenue Molière, 67098 Strasbourg, France. Serge.RIVERA@chru-strasbourg.fr
Villega
Frédéric
F
de Saint-Martin
Anne
A
Matis
Jacqueline
J
Escande
Benoît
B
Chaigne
Denys
D
Astruc
Dominique
D
D000927:Anticonvulsants / Q000627:therapeutic use; D001494:Baths; D002998:Clonazepam / Q000627:therapeutic use; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D009122:Muscle Hypertonia / Q000151:congenital* / Q000188:drug therapy; D009622:Noise; D013216:Reflex, Startle; D014110:Touch
D000927:Anticonvulsants; D002998:Clonazepam