TUBGCP2 and Global developmental delay: Moreover, the TUBGCP2 variants were found to cause lissencephaly spectrum diseases, with the main clinical manifestations being microcephaly, lissencephaly (including agyria, pachygyria, or subcortical band heterotopia), dysmorphic facial features (e.g., narrow forehead, thick eyebrows, bulbous nose, prominent ears, and widened and separated teeth), and developmental delay, with or without seizures.