The pathogenic de novo missense SMARCB1 variant (c.110G > A; p.Arg37His) identified in four patients with severe intellectual disability, choroid plexus hyperplasia and resultant hydrocephalus termed ID-CPH is located within exon 2 of SMARCB1, encoding the winged-helix DNA-binding domain (WHD) [217]. Here, SMARCB1 is linked to Hydrocephalus.