Malformations of cortical development (MCD) represent a large group of brain cortical anomalies characterized by distinctive MRI findings. This ‘radiologically-based’ classification required re evaluation over time on identified underlying mechanisms (cytogenetic and/or molecular). The understanding of genotype findings (nature of cytogenetic/molecular mutation, cellular pathways consequences, timing, …) draw line of evidence on these distinctive group of conditions whereas sometimes precise and constant recurrent genotype/phenotype correlation may not be present.

The clinical diagnosis of MCD is often difficult due to variability and rarity of individual types of malformations. Recent studies have established a relationship between lissencephaly and pathogenic variants in genes involved in the kinesin/tubulin pathways, as the KIF5C gene. Pathogenic variants in the KIF5C gene are a more recently discovered cause of severe developmental delay with epilepsy, characterized by specific malformation of cortical development such as pachygyria. Only seven children have been described to date. We report the natural history of a sixteen years old patient identified carrier of a KIF5C gene mutation who developed infantile epilepsy. We then gather phenotype description and molecular results of all reported patients so far in order to better define this entity.

皮质发育畸形（MCD）代表了一大批以独特的MRI发现为特征的大脑皮质异常。这种“基于放射学的”分类需要随着时间的推移，对确定的潜在机制（细胞遗传学和/或分子）进行重新评估。对基因型发现（细胞遗传学/分子突变的性质，细胞途径的后果，时机等）的理解为这些独特的病症组提供了证据，而有时可能不存在精确且恒定的复发性基因型/表型相关性。

由于个别类型的畸形的变异性和稀有性，MCD的临床诊断通常很困难。最近的研究已经建立了与驱动蛋白/微管蛋白途径有关的基因中的脑性脑病和致病变异之间的关系，如KIF5C基因。KIF5C基因中的致病性变异是最近发现的癫痫严重发育延迟的原因，其特征是皮质发育的特定畸形，例如厚生不明。迄今为止，仅描述了七个孩子。我们报告了16岁患者识别出的KIF5C携带者的自然史发生婴儿癫痫的基因突变。然后，我们收集到目前为止所有已报告患者的表型描述和分子结果，以便更好地定义该实体。