In our study, we found a NM_000425.5:c.2491del:p.(Val831Serfs*20) variant, located in the exon 19 of L1CAM (chrX:153131214), that could damage the L1CAM function by producing a frameshift in the translation of fibronectin type‐III of L1CAM, resulting in the bilateral ventriculomegaly with dilatation of the third ventricle, polyhydramnios, callosal agenesis, and lissencephaly. Here, L1CAM is linked to Lissencephaly.