Lewy body pathology and Alzheimer disease in Down syndrome

Aging adults with Down syndrome (DS) develop Alzheimer disease neuropathology (AD) by the age of 40 years, primarily due to the overexpression of the amyloid precursor protein on chromosome 21. Lewy bodies (LBs) are observed in 7-60% of AD patients in the amygdala and in cortex. As we hypothesized that LB pathology would also be present in DS brain with similar locations and prevalence to AD, we evaluated the frequency of LB in a cohort of DS cases collected over the past 25 years. Neuropathology reports from 55 cases with DS were included in this study. We identified 6 cases (10.9%), all male, with a mean age of 57 years (SD=3) that showed LB and/or Lewy neurites. Five cases were BRAAK stage 6 and one was stage 5. The observation that all our LB positive cases were male may reflect a sample bias. In our study, Lewy pathology was most common in amygdala but other sites of involvement are seen similar to a prior DS study and AD studies. Prior DS studies (n=20-56 cases) found the frequency of LB pathology to range between 8-50% of cases being affected. The prevalence of LB in our DS cohort (10.9%) is in the low end of the range seen in other DS and AD studies.

Source: Movassaghi, M., Lou, J.J., Wright, S., Silva, J., Leavy, K., Kim, R., Monuki, E.S., Perez-Rosendahl, M., Head, E., & Yong, W.H. Lewy body pathology and Alzheimer disease in Down syndrome. American Journal of Clinical Pathology, 2022 Nov., 158(Supp 1), S33, https://doi.org/10.1093/ajcp/aqac126.059