Isolated cloverleaf skull syndrome is a form of craniosynostosis involving multiple sutures (coronal, lambdoidal, sagittal and metopic) characterized by a trilobular skull of varying severity (frontal towering and bossing, temporal bulging and a flat posterior skull), dysmorphic features (downslanting palpebral fissures, midface hypoplasia, and extreme proptosis) and that is complicated by hydrocephalus, cerebral venous hypertension, developmental delay/intellectual disability and hind brain herniation. The disease is Monarch Disease Ontology id MONDO_0007861 (isolated cloverleaf skull syndrome).