Table 1.

FTLD-U Subtypes according to Cairns et al [32].

	Type I	Type II	Type III	Type IV
Characteristic histology	Long dystrophic neurites	NCI, including granular “pre- inclusions”	NCI and short neurites; NII in some	Many NII
Cortical layers most affected	Superficial and middle	Superficial and deep	Superficial	Superficial and middle
Dentate gyrus	Round NCI	Variable granular, crescent or round NCI	Variable crescent or round NCI	No NCI
Clinical feature	Many patients have semantic dementia	Some patients have motor neuron disease	Most patients have frontotemporal dementia	Most patients have frontotemporal dementia
Genetic linkage	None known	9p chromosome linkage	PGRN	VCP