Lateralized periodic discharges due to mutated PLEKHG2 in an infant with congenital nephrotic syndrome: a case report and literature review.

Background: Congenital nephrotic syndrome (CNS) is a rare renal disorder in infants, characterized by significant proteinuria, hypoalbuminemia, edema, and hyperlipidemia, while neurological manifestations are uncommon. Pleckstrin homology and RhoGEF domain containing G2 (PLEKHG2) gene plays a crucial role in the maturation and development of axons, dendrites, and spines. Variants in the PLEKHG2 gene have previously been linked to the development of infantile-onset epileptic encephalopathy. Case Description: We report a male infant with CNS who experienced jerky myoclonus and partial seizures since the neonatal period. Electroencephalography (EEG) revealed lateralized periodic discharges (LPDs), characterized by a triphasic wave pattern. Whole exome sequencing identified two heterozygous variants in the NPHS1 gene, as well as one heterozygous and one homozygous variant in the PLEKHG2 gene. The variants in the PLEKHG2 gene were identified as the likely pathogenic responsible for the myoclonus and seizures. A comprehensive review of the existing literature was conducted to highlight the limited understanding of PLEKHG2 gene variants, their clinical manifestations, and their potential association with LPDs due to brain white matter injury. Conclusions: Our case highlights the link between PLEKHG2 gene variants and LPDs in congenital CNS. It underscores the importance of recognizing EEG patterns associated with these variants and calls for further research into their molecular mechanisms, clinical manifestations, and potential therapies.