Dynamic changes in the corpus callosum in a case of HIVEP2-related disorder: a case report and literature review.

BACKGROUND: Autosomal dominant intellectual developmental disorder type 43 (MRD43) is a rare neurodevelopmental disorder caused by mutations in the HIVEP2 gene. Although previous cases have established core phenotypic features, detailed descriptions of neuroimaging evolution and effective epilepsy management strategies remain limited. This case presents novel findings: it identifies a previously unreported pathogenic variant, documents dynamic changes in the corpus callosum, and details a successful combination antiepileptic drug regimen, providing comprehensive insights into the natural course and clinical management of this disorder. CASE PRESENTATION: We report a 14-year-old male who presented with global developmental delay, intellectual disability, and epilepsy. An initial brain magnetic resonance imaging (MRI) suggested slight thinning of the corpus callosum (involving the genu, rostrum, and body), though a subsequent review found no abnormalities. Genetic testing identified a novel de novo pathogenic variant in the HIVEP2 gene (NM_006734.4: c.3412 C > T, p.Q1138X), confirming the diagnosis of MRD43. His seizures were effectively controlled with a combination of levetiracetam and lamotrigine, which was accompanied by improvement in his electroencephalogram findings. CONCLUSIONS: This case expands the clinical and radiological spectrum of MRD43. The observation of evolving corpus callosum abnormalities suggests a previously underappreciated progressive neurodevelopmental component to the disorder. Furthermore, the positive response to combination antiepileptic therapy offers a practical management reference for clinicians. This report underscores the importance of longitudinal neuroimaging and tailored treatment in managing HIVEP2-related disorders.