CD33 and early-onset autosomal dominant Alzheimer disease: Notably, the patterns of cognitive variation attributed to CD33 SNPs correlate with the cognitive deficit profiles of Alzheimer’s disease and do not align with Parkinson’s disease-associated cognitive impairments, which predominantly impact executive and visuospatial functions.24,25 These results also show the effect of CD33 SNPs to be more specific to the pathogenesis of Alzheimer’s disease, but not to Parkinson’s disease or other neurodegenerative diseases.