A New Case With Cortical Malformation Caused by Biallelic Variants in LAMC3

OBJECTIVE: In this study, we report the case of a 24-year-old man with intellectual disability and childhood-onset seizures. This patient had newly identified biallelic variants in the laminin subunit gamma 3 (LAMC3) gene with unreported cortical malformation. METHODS: Exome sequencing. RESULTS: Genetic analyses revealed new biallelic variants in the LAMC3 gene. An MRI examination of the brain revealed cortical malformations predominantly in the temporal lobes and mildly in the occipital, frontal, and parietal lobes. In addition, our patient also exhibited mild midline malformation in the ventral pons, which is unique to LAMC3 variants. DISCUSSION: Patients with LAMC3 variants have been reported to exhibit cortical malformation predominantly in the occipital lobes, but this patient exhibited cortical malformation predominantly in the temporal lobes and mildly in the occipital, frontal, and parietal lobes. In addition, this patient also exhibited mild midline malformation in the ventral pons. These unique findings cast new light on the role of LAMC3 in brain development.