A novel splice variant expands the LAMC3 ‐associated cortical phenotype to frontal only polymicrogyria and adult‐onset epilepsy

Bi‐allelic loss‐of‐function variants in LAMC3 , encoding extracellular matrix protein laminin gamma 3, represent a rare cause of occipital polymicrogyria with epilepsy, developmental delay and cognitive impairment. So far, only five families have been reported. We now identified a novel, homozygous splice variant in LAMC3 in an individual with an unusual manifestation of cortical malformation. She presented with polymicrogyria in the frontal but not the occipital lobes, with adult‐onset seizures and normal psychomotor development and cognition. Additionally, ictal asystole, requiring implantation of a pacemaker, and nonepileptic seizures occurred. This case expands the spectrum of LAMC3 ‐associated cortical malformation phenotypes to frontal only polymicrogyria and adult‐onset of epilepsy.