Immunotherapy in selected patients with Down syndrome disintegrative disorder

Down syndrome disintegrative disorder (DSDD) is an increasingly identified condition characterized by cognitive decline, autistic characteristics, insomnia, catatonia, and psychosis in adolescents and young adults with Down syndrome. Previously we reported a higher rate of autoimmune thyroid disease in these patients compared with unaffected individuals with Down syndrome. We therefore hypothesized DSDD may in some cases be immune-mediated. Here we report four cases of DSDD treated with immunotherapy. Families were interviewed retrospectively for symptoms of cognitive decline, autism, catatonia, psychosis, and insomnia before and after treatment, using established scales where possible. Medical records were reviewed for evaluations and treatment. All four patients received intravenous immunoglobulin with or without additional immunotherapy. Significant improvements were seen in catatonia, insomnia, autistic features, cognition, and psychosis. In this small case series of patients with autoimmunity, core symptoms of DSDD improved significantly after immunotherapy. This supports the hypothesis that, in some patients, DSDD is immune-mediated. Immunotherapy should be considered in the treatment of DSDD, particularly in patients with a history of autoimmunity. WHAT THIS PAPER ADDS: Immunotherapy may improve symptoms of catatonia, insomnia, autism severity, cognitive decline, and psychosis in Down syndrome disintegrative disorder.