MAPT and frontotemporal dementia: Finally, differentiation outcomes were not associated with particular disease-causing mutations or genotypes, with partly cortical differentiations (dorsalized plus partially ventralized) being generated from lines derived from control individuals (76%) and individuals affected by sporadic Alzheimer’s disease (67%), Down syndrome (trisomy 21; TS21) (61%) or frontotemporal dementia due to MAPT Ex10+16 mutations (58%), though in the latter category, more of the differentiations had a partially ventralized phenotype (Figure 5C).