Abnormal Brain Iron Accumulation is a Rare Finding in Down Syndrome Regression Disorder

Down syndrome regression disorder (DSRD) is characterized by the sudden loss of adaptive function, cognitive-executive function, and language with abnormal sleep and/or motor control.Clinical, laboratory, and imaging data from three individuals with DSRD and iron on brain imaging were reviewed.Three patients with Down syndrome presented with new onset of flat affect, depression, reduced speech, and other neurological symptoms consistent with DSRD. Magnetic resonance imaging showed abnormal iron accumulation in the basal ganglia, as well as calcification in two cases. Molecular diagnostic testing for neurodegeneration with brain iron accumulation was negative in the two individuals tested.These individuals presented suggest that a subset of individuals with DSRD have abnormal brain iron accumulation. Motor control symptoms reported in DSRD, such as stereotypies and parkinsonism, may reflect this basal ganglia involvement. The presence of abnormal brain iron should not delay or preclude diagnosis and treatment for DSRD.