Association study to evaluate the serotonin transporter and apolipoprotein E genes in frontotemporal lobar degeneration in Italy

Frontotemporal lobar degeneration (FTLD) is a progressive neurodegenerative disorder characterized by behavioral and language disturbances. We performed a case-control association study in the Italian population to assess the relevance for FTLD genetic susceptibility of the serotonin (5-HT) transporter gene-linked polymorphic region [rs4795541, alias short (S)/long (L)] an in/del polymorphism of the promoter region of the gene coding for the 5-HT transporter (SLC6A4). This functional polymorphism was reported to influence the SLC6A4 transcription rate, with the S-allele having a two-fold reduced efficiency. We collected 225 independent subjects (74 sporadic FTLD and 151 age-matched healthy controls, CT) that were genotyped for the rs4795541, the SLC6A4 single nucleotide polymorphisms (SNP) rs25531 and rs6354, and the apolipoprotein E (APOE) allelic variants. A significant correlation [P = 0.018, OR (95% CI): 2.1 (1.1-3.9)] between rs4795541 S-allele presence and FTLD susceptibility was found. In summary, the rs4795541 might be important for FTLD susceptibility in the Italian population.