From these findings, we postulated that differences might exist in the CSF levels of NFL, YKL-40, and Aβ1-38, the number and distribution of cortical areas, the lateral predominance (left-right difference) of lobar CMBs localization, as well as the regional CBF (cerebral blood flow) volume and 11C PiB retention may be apparent between the four subtypes of AD. The gene discussed is NEFL; the disease is Alzheimer disease.