NEUROD2-related disorder with neonatal onset: case report and review of the literature

The NEUROD2 gene encodes a transcription factor essential for neuronal differentiation and cortical development. Pathogenic variants cause a rare autosomal dominant neurodevelopmental disorder with variable expressivity, typically presenting in early infancy with developmental delay, epilepsy, and behavioral abnormalities. We report a newborn girl carrying a de novo heterozygous missense variant NM_006160.4:c.790G>A, p.(Ala264Thr), located outside the canonical basic helix-loop-helix (bHLH) domain. Soon after birth, she presented respiratory depression, hypotonia, feeding difficulties, and electrographic seizures. Magnetic resonance imaging (MRI) showed subcortical white matter hyperintensity, and the electroencephalogram (EEG) revealed abnormal background activity. During follow-up, epilepsy was controlled, but neurodevelopmental delay with autistic features emerged. This case represents the earliest reported clinical onset associated with NEUROD2 variants and expands the phenotypic and mutational spectrum. It highlights that variants outside known hotspots can cause severe disease and supports including NEUROD2 in the differential diagnosis of neonatal neurological impairment.