Our goal was to describe and illustrate prenatal cerebral imaging features of the most severe form of a new syndromic entity related to KIAA1109 pathogenic variants based on a retrospective multicentric study of seven cases. All cases demonstrated a similar complex severe cerebral malformative pattern. This pattern included, within the supratentorial space, major cerebral parenchymal thinning with a lissencephalic cortical pattern, voluminous germinal matrices, severe ventriculomegaly, and corpus callosum agenesis. Within the infra-tentorial space, cerebellar hypoplasia was associated with characteristic brainstem dysgenesis including elongation of the pons, as well as a variable degree of kinking of the brainstem. This cerebral pattern, which was suggestive of the more severe phenotypes related to disrupting variants of tubulin-encoding genes, was associated in all cases with clubfoot and/or arthrogryposis, and in most cases with cardiac and ophthalmologic anomalies. In all cases, exome sequencing led to the identification of KIAA1109 pathogenic variants.