CAA and related co‐morbidities in Down syndrome and Alzheimer disease

Abstract

AbstractBackgroundCerebral amyloid angiopathy (CAA) is a form of cerebrovascular pathology characterized by the deposition of beta‐amyloid in the leptomeningeal and cortical blood vessels of the brain. CAA is a critical factor contributing to dementia in sporadic Alzheimer’s disease (AD). Many individuals with Down syndrome (DS) develop CAA due to the overexpression of the amyloid precursor protein (APP) gene and the subsequent increase of beta‐amyloid in the brain. However, little is known about the role of co‐morbidities like seizures in the presence and severity of CAA, or the effect that CAA has on the course of AD in individuals with DS.MethodClinical and neuropathology data for 48 individuals were included in the study. The clinical data, including the presence or absence of seizures and APOE genotype, was collected prospectively as part of a longitudinal research protocol for AD in DS at UCI as well as through a retrospective chart review of the medical records of patients at the AD in DS Memory Care Clinic at UCI. The neuropathology data, including the presence and severity of CAA, was recorded using the guidelines of the National Alzheimer’s Coordinating Committee (NACC).ResultA greater percentage of individuals with seizures have CAA as compared to those who did not have seizures, although the presence of seizures does not appear to impact the severity of CAA. Regarding those individuals with the APOE e4 allele, the majority of these individuals experienced moderate or severe CAA, with relatively few individuals with mild CAA or none. The duration of AD course appeared to decrease as CAA severity increased, but the results were not conclusive.ConclusionOverall, we did not find a significant correlation between seizures and the presence or absence of CAA, or between the severity of CAA and the duration of AD course. Some limitations to our study included a limited number of individuals without CAA or seizures compared to those who presented these conditions. Continuing studies will reinforce the role of CAA in the development of AD and contribute to our understanding of the role of clinical co‐morbidities in AD progression.