A challenging case of Down syndrome regression disorder.

Abstract: Down syndrome regression disorder (DSRD) is a rare cause of neuropsychiatric regression observed in previously-healthy individuals with Down syndrome (DS). There have been reports of brain iron accumulation in the basal ganglia of patients with DS and DSRD, although the underlying etiology remains unclear. The current study aims to report, through detailed neuroimaging, laboratory tests, and clinical data findings, the case of a patient with DS who experienced a significant loss of abilities, accompanied by neuroimaging findings indicative of abnormal brain iron accumulation. While an extensive investigation with blood, cerebrospinal fluid (CSF), and genetic markers was unremarkable, magnetic resonance imaging (MRI) scans revealed abnormal iron deposition and calcifications in the globus pallidus. The abnormal iron accumulation in the basal ganglia of patients with DSRD could be a potential neuroimaging marker for this condition.