APOE and early-onset autosomal dominant Alzheimer disease: We also performed a similar analysis in respect of Apolipoprotein E (APOE) genotype since there have many studies claiming an increased frequency of APOE ε4 allele in FTLD (see [30–33] for examples) and this might operate by facilitating pathological changes, as it does in Alzheimer’s disease where possession of APOE ε4 allele is associated with increased deposition of amyloid β protein [34] and cerebral amyloid angiopathy [35].