In January 2023, the Down Syndrome Medical Interest Group - USA (DSMIG-USA) shared a consensus update for families on Down syndrome regression disorder (DSRD, also called Down syndrome disintegrative disorder, unexplained regression in Down syndrome, and others). The document describes DSRD, lists associated symptoms, and discusses diagnosis and treatment.
Additional information is available on the DSMIG-USA Regression page and in the Decline in Skills and Regression section of our Resource Library.