TY - JOUR
T1 - KCNQ2 encephalopathy
T2 - A case due to a de novo deletion
AU - Spagnoli, Carlotta
AU - Salerno, Grazia Gabriella
AU - Iodice, Alessandro
AU - Frattini, Daniele
AU - Pisani, Francesco
AU - Fusco, Carlo
PY - 2017/2/3
Y1 - 2017/2/3
N2 - KCNQ2 encephalopathy is characterized by severely abnormal EEG, neonatal-onset epilepsy and developmental delay. It is caused by mutations (typically missense) in the KCNQ2 gene, encoding the voltage gated potassium channel Kv7.2 and leading to a negative-dominant effect. We present one case experiencing recurrent neonatal seizures with changing hemispheres of origin, reminiscent of epilepsy of infancy with migrating focal seizures. At 9. months of age the patient is still seizure-free on carbamazepine, although he is developing a spastic-dystonic tetraplegia with severe dysphagia. He harbors a de novo deletion (c.913_915del [p.Phe305del)]), only described once in a couple of severely affected twins, and leading to the deletion of a phenylalanine residue in the pore domain of the channel. In conclusion, our case is the second described with encephalopathy due to this specific deletion (the one and only deletion so far reported in KCNQ2 encephalopathy). Thus, deletion is a newly described mechanism highlighting how not only missense mutations but also deletions in the channel hot spots can lead to a severe phenotype. Furthermore he presented ictal EEG features similar to epilepsy of infancy with migrating focal seizures not previously described.
AB - KCNQ2 encephalopathy is characterized by severely abnormal EEG, neonatal-onset epilepsy and developmental delay. It is caused by mutations (typically missense) in the KCNQ2 gene, encoding the voltage gated potassium channel Kv7.2 and leading to a negative-dominant effect. We present one case experiencing recurrent neonatal seizures with changing hemispheres of origin, reminiscent of epilepsy of infancy with migrating focal seizures. At 9. months of age the patient is still seizure-free on carbamazepine, although he is developing a spastic-dystonic tetraplegia with severe dysphagia. He harbors a de novo deletion (c.913_915del [p.Phe305del)]), only described once in a couple of severely affected twins, and leading to the deletion of a phenylalanine residue in the pore domain of the channel. In conclusion, our case is the second described with encephalopathy due to this specific deletion (the one and only deletion so far reported in KCNQ2 encephalopathy). Thus, deletion is a newly described mechanism highlighting how not only missense mutations but also deletions in the channel hot spots can lead to a severe phenotype. Furthermore he presented ictal EEG features similar to epilepsy of infancy with migrating focal seizures not previously described.
KW - Deletion
KW - EEG
KW - Genetic
KW - KCNQ2 encephalopathy
KW - Neonatal-onset epilepsy
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UR - http://www.scopus.com/inward/citedby.url?scp=85024088798&partnerID=8YFLogxK
U2 - 10.1016/j.braindev.2017.06.008
DO - 10.1016/j.braindev.2017.06.008
M3 - Article
AN - SCOPUS:85024088798
JO - Brain and Development
JF - Brain and Development
SN - 0387-7604
ER -