PURPOSE KCNQ2 mutations are associated with benign familial neonatal epilepsy (BFNE) or developmental and epileptic encephalopathy (DEE). In this study, we aimed to delineate the phenotype of KCNQ2 encephalopathy and evaluate the treatment response. METHODS Thirteen patients of KCNQ2 encephalopathy were included in the study. Characteristics of KCNQ2 mutations, electroclinical features, clinical course, and response to the treatment were analyzed. RESULTS Age range of the thirteen patients was between 3 months and 20.9 years. The onset of seizures in 11 patients ranged from 1 to 3 days of age, while in the other two patients it was 7 and 40 days, respectively. Most common initial seizure types were tonic seizures. Initial EEGs were suppression burst pattern in seven patients and slow and disorganized background with multifocal epileptiform discharges in six patients. Initial epilepsy syndrome was Ohtahara syndrome in seven patients, neonatal focal seizure in five patients, and focal epilepsy beyond neonatal period in one patient. Sodium channel blockers including oxcarbazepine (OXC) (n = 3), lamotrigine (LTG) (n = 3), phenytoin (PHT) (n = 2), topiramate (TPM) (n = 2), and zonisamide (ZNS) (n = 1) were tried and found effective in eleven patients. Ultimately, 12 of 13 patients became seizure-free. However, developmental outcomes were poor. CONCLUSIONS Sodium channel blockers are effective in seizure control in these patients with KCNQ2 encephalopathy. Early recognition of KCNQ2 encephalopathy and early use of sodium channel blockers might be helpful in seizure control.

中文翻译：

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KCNQ2脑病的临床特征

目的 KCNQ2 突变与良性家族性新生儿癫痫 (BFNE) 或发育性和癫痫性脑病 (DEE) 相关。在这项研究中，我们旨在描绘 KCNQ2 脑病的表型并评估治疗反应。方法 13 名 KCNQ2 脑病患者纳入研究。分析了 KCNQ2 突变的特征、电临床特征、临床过程和对治疗的反应。结果 13 名患者的年龄范围在 3 个月至 20.9 岁之间。11 名患者的癫痫发作时间为 1 至 3 天，而另外两名患者分别为 7 天和 40 天。最常见的初始癫痫发作类型是强直性癫痫发作。7 名患者的初始脑电图为抑制爆发模式，6 名患者的脑电图为缓慢且杂乱无章的多灶性癫痫样放电背景。最初的癫痫综合征 7 例为 Ohtahara 综合征，5 例为新生儿局灶性癫痫，1 例为新生儿期后局灶性癫痫。钠通道阻滞剂包括奥卡西平 (OXC) (n = 3)、拉莫三嗪 (LTG) (n = 3)、苯妥英 (PHT) (n = 2)、托吡酯 (TPM) (n = 2) 和唑尼沙胺 (ZNS) ( n = 1) 在 11 名患者中进行了尝试并发现有效。最终，13 名患者中有 12 名不再癫痫发作。然而，发展成果很差。结论钠通道阻滞剂可有效控制这些 KCNQ2 脑病患者的癫痫发作。