Intellectual disability, neuroregression and adult-onset progressive dystonia due to a DLG4 pathogenic variant.

We report a 34-year-old male with childhood developmental delay, severe intellectual disability in adulthood, episodes of agitation with a previous diagnosis of schizoaffective disorder and adult-onset cognitive regression who developed progressive generalised dystonia due to a de novo DLG4 pathogenic loss-of-function variant. This case expands the phenotypic spectrum of recognised movement disorder manifestations associated with DLG4-related synaptopathy.