Fig. 1: Genetic and pedigree analysis of a family with focal epilepsy and focal cortical dysplasia associated with a novel FOXJ3 variant.

A Pedigree of a family with focal epilepsy and focal cortical dysplasia harboring a FOXJ3 missense variant (c.1052 A > G; p.Asn351Ser). Filled symbols represent individuals affected by epilepsy (DNA #50, 51, and 55), while gray-filled symbols indicate carriers of the FOXJ3 p.N351S variant without epilepsy (DNA #56). The asterisk symbol denotes the index patient. Individuals selected for WGS are marked with green circles (DNA #50, 55, and 57). B Coronal section from serial brain MRIs of the 6-year-old FCD type II index patient (IV-4). The imaging highlights the blurring of the grey/white matter boundary (red box). C Representative histopathological images of the index patient showing FCD type IIa with cortical dyslamination (left, H&E stain, scale bar = 100 μm). Dysmorphic neurons with enlarged somata and nuclei, along with aggregates of Nissl substance, are evident (middle, H&E stain, scale bar = 50 μm). No balloon cells were identified. NeuN immunohistochemistry highlights the abnormal neuronal morphology (right, NeuN stain, scale bar = 50 μm). Similar histopathological features were consistently observed across all five independent sections examined. D Variants identified from WGS include 65,536 SNPs and 49,526 indels. Filtering for exonic, splicing, and non-synonymous variants retained 185 SNPs. Subsequent filtering for population frequency (<0.001) in public databases yielded 2 SNPs and 13 indels. Intrafamilial segregation analysis identified the FOXJ3 c.1052 A > G variant (p.N351S) as segregating with the epilepsy phenotype. E Electropherograms confirmed the heterozygous FOXJ3 variant (c.1052 A > G; p. Asn351Ser) in the index patient (DNA No. 50), and affected family members (DNA No. 51, 55, 56), but not in unaffected individuals (DNA No. 52). This finding was validated by Sanger sequencing.