GLI3 and Greig cephalopolysyndactyly syndrome: Intellectual disability and developmental delay together with hydrocephalus and seizures are included in a more severe clinical phenotype [4, 6, 7] associated with a variant disorder characterized by a worse prognosis: the Greig cephalopolysyndactyly-contiguous gene syndrome (GCPS-CGS), caused by mutations larger than 1 Mb in the GLI3 gene [8, 9].