Neonatal seizures and long QT syndrome: a cardiocerebral channelopathy?
We identified a patient with electrophysiologically verified neonatal long QT syndrome (LQTS) and neonatal seizures in the presence of a controlled cardiac rhythm. To find a cause for this unusual combination of phenotypes, we tested the patient for mutations in seven ion channel genes associated with either LQTS or benign familial neonatal seizures (BFNS). Comparative genome hybridization (CGH) was done to exclude the possibility of a contiguous gene syndrome. No mutations were found in the genes (KCNQ2, KCNQ3) associated with BFNS, and CGH was negative. A previously described mutation and a known rare variant were found in the LQTS-associated genes SCN5A and KCNE2. Both are expressed in the brain, and although mutations have not been associated with epilepsy, we propose a pathophysiologic mechanism by which the combination of molecular changes may cause seizures.
Heron
Sarah E
SE
SA Pathology at Women's and Children's Hospital, North Adelaide, SA, Australia. sarah.heron@adelaide.edu.au
Hernandez
Marta
M
Edwards
Caitlin
C
Edkins
Edward
E
Jansen
Floor E
FE
Scheffer
Ingrid E
IE
Berkovic
Samuel F
SF
Mulley
John C
JC
D053447:Channelopathies / Q000175:diagnosis* / Q000453:epidemiology / Q000235:genetics; D002675:Child, Preschool; D004562:Electrocardiography / Q000706:statistics & numerical data; D004569:Electroencephalography / Q000706:statistics & numerical data; D004827:Epilepsy / Q000175:diagnosis / Q000235:genetics; D020936:Epilepsy, Benign Neonatal / Q000175:diagnosis* / Q000453:epidemiology / Q000235:genetics; D006801:Humans; D007231:Infant, Newborn; D051658:KCNQ2 Potassium Channel / Q000235:genetics; D051659:KCNQ3 Potassium Channel / Q000235:genetics; D008133:Long QT Syndrome / Q000175:diagnosis* / Q000453:epidemiology / Q000235:genetics; D008297:Male; D009124:Muscle Proteins / Q000235:genetics; D009154:Mutation / Q000235:genetics; D062554:NAV1.5 Voltage-Gated Sodium Channel; D009693:Nucleic Acid Hybridization / Q000379:methods; D010641:Phenotype; D012640:Seizures / Q000235:genetics; D015222:Sodium Channels / Q000235:genetics
D051658:KCNQ2 Potassium Channel; D051659:KCNQ3 Potassium Channel; D009124:Muscle Proteins; D062554:NAV1.5 Voltage-Gated Sodium Channel; C568320:SCN5A protein, human; D015222:Sodium Channels