Cerebral Amyloid Angiopathy–Related Inflammation in Down Syndrome–Related Alzheimer Disease

A 59-year-old woman with Down syndrome (DS) and prodromal Alzheimer disease (AD) presenting progressive cognitive impairment in the previous year, with no focal symptoms, headache, seizures, or accelerated cognitive decline, underwent 3T brain MRI showing cortico-subcortical tumefactive fluid-attenuated inversion recovery (FLAIR) hyperintensities, associated with microbleeds and superficial siderosis (Figure 1). These FLAIR abnormalities have moved spatially compared with a previous MRI, suggesting an inflammatory process (Figure 2). The diagnosis of cerebral amyloid angiopathy (CAA)–related inflammation (CAA-ri) was made.1 DS is a genetic form of AD and has increased CAA prevalence.2 As future anti-amyloid trials will likely include individuals with DS, neurologists must be aware of CAA-ri in this population.