DLG4 and Alzheimer disease: A priori, the lack of an interaction between 5-HTTLPR genotype (i.e., S and L alleles) and a diagnosis of AD on 5-HTT mRNA transcription, on 5-HTT glycosylation/expression, and on the levels of synaptic markers of AD progression (i.e., SNAP-25, PSD-95) in our sample set do not support the reported differences in risk of developing AD ascribed to these 5-HTTLPR length polymorphisms.