Background and Purpose

Mutations in KCNQ3 have classically been associated with benign familial neonatal and infantile seizures and more recently identified in patients with neurodevelopmental disorders and abnormal electroencephalogram (EEG) findings. We present 4 affected patients from a family with a pathogenic mutation in KCNQ3 with a unique constellation of clinical findings.

Methods

A family of 3 affected siblings and mother sharing a KCNQ3 pathogenic variant are described, including clinical history, genetic results, and EEG and magnetic resonance imaging (MRI) findings.

Results

This family shows a variety of clinical manifestations, including neonatal seizures, developmental delays, autism spectrum disorder, and anxiety. One child developed absence epilepsy, 2 children have infrequent convulsive seizures that have persisted into childhood, and their parent developed adult-onset epilepsy. An underlying c.1091G>A (R364H) variant in KCNQ3 was found in all affected individuals.

Conclusions

The phenotypic variability of KCNQ3 channelopathies continues to expand as more individuals and families are described, and the variant identified in this family adds to the understanding of the manifestations of KCNQ3-related disorders.

中文翻译：

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共享杂合 KCNQ3 变体的家族中的表型谱

背景和目的

KCNQ3突变通常与良性家族性新生儿和婴儿癫痫发作有关，最近在患有神经发育障碍和脑电图 (EEG) 异常的患者中发现。我们介绍了来自一个具有KCNQ3致病性突变家族的 4 名受影响的患者，这些患者具有独特的临床表现。

方法

描述了一个由 3 个受影响的兄弟姐妹和母亲共享KCNQ3致病变异的家庭，包括临床病史、遗传结果以及脑电图和磁共振成像 (MRI) 发现。

结果

该家族表现出多种临床表现，包括新生儿惊厥、发育迟缓、自闭症谱系障碍和焦虑症。1 名儿童出现失神癫痫，2 名儿童出现持续到儿童期的罕见惊厥性癫痫发作，其父母出现成人癫痫。在所有受影响的个体中发现了KCNQ3中潜在的 c.1091G>A (R364H) 变体。

结论

随着越来越多的个体和家族被描述，KCNQ3 通道病的表型变异性继续扩大，并且在该家族中发现的变异增加了对KCNQ3相关疾病表现的理解。