[Long QT syndrome in children: analysis of the Lyon series].
Congenital long QT syndrome is a rare and serious disorder in children. In addition to the clinical and electrocardiographical diagnostic criteria, molecular biochemistry has identified six genes which are implicated in this pathology. Our study involved a retrospective analysis of 23 patients aged less than 21 with congenital long QT syndrome, followed up for an average of two years. Genotypes were obtained for all of the patients. There were unfortunately two deaths, one of which had a mutation in the SCN5A gene. The other patient had a double mutation of the SCN5A and KCNE2 genes. Symptomatic patients had QT and QTc intervals noticeably longer than the asymptomatic patients, although this difference was not shown to be significant. LQT3 patients as well as those with a double mutation were affected more severely because two of the three LQT3 patients and one of the two patients with a double mutation suffered a cardiac arrest. Three patients in our study showed no mutation. Nevertheless, two of them suffered a severe cardiac event. This confirms the limits of genetic diagnosis, which could be envisaged in all cases. All of the clinical and ECG data should be combined with the genetic analysis in order to confirm the diagnosis.
Iraqi
M
M
Service de cardiologie pédiatrique, Hôpital Louis Pradel, Lyon. meryem.iraqi@free.fr
Chevalier
P
P
Raboisson
M J
MJ
Bozio
A
A
Bouvagnet
P
P
Millat
G
G
Rodriguez-Lafrasse
C
C
D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D005260:Female; D005602:France; D005838:Genotype; D006323:Heart Arrest / Q000209:etiology; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008133:Long QT Syndrome / Q000151:congenital* / Q000235:genetics*; D008297:Male; D009124:Muscle Proteins / Q000235:genetics; D009154:Mutation; D062554:NAV1.5 Voltage-Gated Sodium Channel; D024642:Potassium Channels, Voltage-Gated / Q000235:genetics; D012189:Retrospective Studies; D015222:Sodium Channels / Q000235:genetics
C489619:KCNE2 protein, human; D009124:Muscle Proteins; D062554:NAV1.5 Voltage-Gated Sodium Channel; D024642:Potassium Channels, Voltage-Gated; C568320:SCN5A protein, human; D015222:Sodium Channels