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Neuropediatrics 2023; 54(05): 297-307
DOI: 10.1055/a-2060-4576
Review Article

KCNQ2-Related Epilepsy: Genotype–Phenotype Relationship with Tailored Antiseizure Medication (ASM)—A Systematic Review

Raffaele Falsaperla
1   Neonatal Intensive Care Unit and Neonatal Accompaniment Unit, Azienda Ospedaliero-Universitaria Policlinico “Rodolico-San Marco”, San Marco Hospital, University of Catania, Catania, Italy
2   Unit of Clinical Paediatrics, Azienda Ospedaliero-Universitaria Policlinico, “Rodolico-San Marco”, San Marco Hospital, Catania, Italy
,
Roberta Criscione
3   Neonatal Intensive Care Unit and Neonatal Accompaniment Unit, Azienda Ospedaliero-Universitaria Policlinico “Rodolico-San Marco”, Postgraduate Training Program in Pediatrics, University of Catania, Catania, Italy
,
Carla Cimino
1   Neonatal Intensive Care Unit and Neonatal Accompaniment Unit, Azienda Ospedaliero-Universitaria Policlinico “Rodolico-San Marco”, San Marco Hospital, University of Catania, Catania, Italy
,
Francesco Pisani
4   Child Neuropsychiatry Unit, Human Neuroscience Department, Sapienza University of Rome, Italy
,
Martino Ruggieri
5   Unit of Clinical Pediatrics, Department of Clinical and Experimental Medicine, University of Catania, AOU “Policlinico”, PO “G. Rodolico”, Catania, Italy
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Abstract

Background Autosomal dominant mutations of the KCNQ2 gene can cause two epileptic disorders: benign familial neonatal seizures (BFNS) and developmental epileptic encephalopathy (DEE). This systematic review aims to identify the best reported therapy for these patients, relating to phenotype, neurodevelopmental outcome, and an eventual correlation between phenotype and genotype.

Methods We searched on PubMed using the search terms “KCNQ2” AND “therapy” and “KCNQ2” AND “treatment”; we found 304 articles. Of these, 29 met our criteria. We collected the data from 194 patients. All 29 articles were retrospective studies.

Results In all, 104 patients were classified as DEE and 90 as BFNS. After treatment began, 95% of BFNS patients became seizure free, whereas the seizures stopped only in 73% of those with DEE. Phenobarbital and sodium channel blockers were the most used treatment in BFNS. Most of the DEE patients (95%) needed polytherapy for seizure control and even that did not prevent subsequent developmental impairment (77%).

Missense mutations were discovered in 96% of DEE patients; these were less common in BFNS (50%), followed by large deletion (16%), truncation (16%), splice donor site (10%), and frameshift (7%).

Conclusion Phenobarbital or carbamazepine appears to be the most effective antiseizure medication for children with a “benign” variant. On the contrary, polytherapy is often needed for DEE patients, even if it does not seem to improve neurological outcomes. In DEE patients, most mutations were located in S4 and S6 helix, which could serve as a potential target for the development of more specific treatment in the future.

Keywords

KCNQ2 - epilepsy - encephalopathy


Publication History

Received: 09 September 2022

Accepted: 15 March 2023

Accepted Manuscript online:
22 March 2023

Article published online:
15 May 2023

© 2023. Thieme. All rights reserved.

Georg Thieme Verlag KG
Rüdigerstraße 14, 70469 Stuttgart, Germany

 

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