Clinical features and genetic analysis of epilepsy caused by CLCN4 gene mutation: a case report and literature review.

Abstract

Background: Epilepsy is a prevalent chronic neurological disorder that affects individuals across all age groups. Genetic factors are believed to play a significant role in the etiology of epilepsy; however, epilepsy associated with mutations in the chloride voltage-gated channel 4 (CLCN4) gene is clinically rare.

Case description: We report a 2-year and 4-month-old male patient who experienced cluster convulsions due to a heterozygous variant in the CLCN4 gene (NM_001830: c.1024G>A, p. Gly342Arg). This patient exhibited focal seizures with impaired consciousness, which responded well to treatment with valproate and lamotrigine, although he presented with mild intellectual disability (ID) and language deficits.

Conclusions: A review of the existing literature identified only 60 cases, demonstrating a wide phenotypic spectrum. ID of varying degrees is observed in the majority of patients. Seizures typically commence in infancy and early childhood and manifest as multiple types, with focal seizures and generalized tonic-clonic seizures being the most common. Notably, missense variants may lead to a more severe phenotype compared to frameshift variants, and the p. Pro369Leu variant may represent a potential hotspot within the CLCN4 gene. Nearly half of the patients exhibit refractory seizures despite treatment with multiple medications, while valproate, levetiracetam, and lamotrigine are considered viable therapeutic options.