%0 Case Reports
%T Pyridoxine-responsive KCNQ2 epileptic encephalopathy: Additional cases and literature review.
%A Chen J
%A Tao Q
%A Fan L
%A Shen Y
%A Liu J
%A Luo H
%A Yang Z
%A Liang M
%A Gan J
%J Mol Genet Genomic Med
%V 10
%N 10
%D 10 2022
%M 35906921
%F 2.473
%R 10.1002/mgg3.2024
%X Typical patients with KCNQ2 (OMIM# 602235) epileptic encephalopathy present early neonatal-onset intractable seizures with a burst suppression EEG pattern and severe developmental delay or regression, and those patients always fail first-line treatment with sodium channel blockers. Vitamin B6, either pyridoxine or pyridoxal 50-phosphate, has been demonstrated to improve seizure control in intractable epilepsy.<BR>Here, we collected and summarized the clinical data for four independent cases diagnosed with pyridoxine-responsive epileptic encephalopathy, and their exome sequencing data. Moreover, we reviewed all published cases and summarized the clinical features, genetic variants, and treatment of pyridoxine-responsive KCNQ2 epileptic encephalopathy.<BR>All four cases showed refractory seizures during the neonatal period or infancy, accompanied by global development delay. Four pathogenetic variants of KCNQ2 were uncovered and confirmed by Sanger sequencing: KCNQ2 [NM_172107.4: c.2312C &gt; T (p.Thr771Ile), c.873G &gt; C (p.Arg291Ser), c.652 T &gt; A (p.Trp218Arg) and c.913-915del (p. Phe305del)]. Sodium channel blockers and other anti-seizure medications failed to control their seizures. The frequency of seizures gradually decreased after treatment with high-dose pyridoxine. In case 1, case 2, and case 4, clinical seizures relapsed when pyridoxine was withdrawn, and seizures were controlled again when pyridoxine treatment was resumed.<BR>Our study suggests that pyridoxine may be a promising adjunctive treatment option for patients with KCNQ2 epileptic encephalopathy.