Triggering Receptor Expressed on Myeloid cells (TREM)2 deficiency originates a 
genetic syndrome characterized by bone cysts and presenile dementia, named 
Nasu-Hakola disease (NHD). Early onset dementia and marked involvement of 
frontal regions are features characterizing both NHD and other kinds of 
neurodegenerative disorders, such as Frontotemporal Lobar Degeneration (FTLD), 
and, in some cases, Alzheimer's disease (AD). Three Single Nucleotide 
Polymorphisms (SNPs) in TREM2 coding region were screened by allelic 
discrimination in a population of probable AD patients as well as FTLD patients 
as compared with age-matched controls. In addition, mutation scanning of the 
coding region of TREM2 gene was carried out in 7 patients with early onset AD 
(EOAD), 16 FTLD, and 20 controls. None of the SNPs analyzed was present, either 
in patients or controls. Moreover, mutation scanning of the five exons of TREM2 
failed to detect the presence of novel polymorphisms. These data demonstrate 
that TREM2 coding region is highly conserved, implying a crucial role of this 
receptor. Further studies, including a functional analysis, are certainly 
required to clarify the role of TREM2 in neurodegenerative processes.