Frontotemporal lobar degeneration (FTLD) represents a group of clinically, 
neuropathologically and genetically heterogeneous disorders with plenty of 
overlaps between the neurodegenerative mechanism and the clinical phenotype. 
FTLD is pathologically characterized by the frontal and temporal lobar atrophy. 
Frontotemporal dementia (FTD) clinically presents with abnormalities of behavior 
and personality and language impairments variants. The clinical spectrum of FTD 
encompasses distinct canonical syndromes: behavioural variant of FTD (bvFTD) and 
primary progressive aphasia. The later includes nonfluent/agrammatic variant PPA 
(nfvPPA or PNFA), semantic variant PPA (svPPA or SD) and logopenic variant PPA 
(lvPPA). In addition, there is also overlap of FTD with motor neuron disease 
(FTD-MND or FTD-ALS), as well as the parkinsonian syndromes, progressive 
supranuclear palsy (PSP) and corticobasal syndrome (CBS). The FTLD spectrum 
disorders are based upon the predominant neuropathological proteins (containing 
inclusions of hyperphosphorylated tau or ubiquitin protein, e.g transactive 
response (TAR) DNA-binding protein 43 kDa (TDP-43) and fusedin-sarcoma protein 
in neurons and glial cells) into three main categories: (1) 
microtubule-associated protein tau (FTLD-Tau); (2) TAR DNA-binding protein-43 
(FTLD-TDP); and (3) fused in sarcoma protein (FTLD-FUS). There are five main 
genes mutations leading clinical and pathological variants in FTLD that 
identified by molecular genetic studies, which are chromosome 9 open reading 
frame 72 (C9ORF72) gene, granulin (GRN) gene, microtubule associated protein tau 
gene (MAPT), the gene encoding valosin-containing protein (VCP) and the charged 
multivesicular body protein 2B (CHMP2B). In this review, recent advances on the 
different clinic variants, neuroimaging, genetics, pathological subtypes and 
clinicopathological associations of FTD will be discussed.