Furthermore, the activation of the proinflammatory pathway (TNF-α), typical of AD, decreases the P-glycoprotein activity and it has been described that iNPH patients show higher levels of CSF TNF-α compared to MCI subjects44 leading to speculate on the role of SP1 as a possible marker for differential diagnosis but also in this case results are contradictory since other publications describe low45 or unchanged46 levels of TNF-α, suggesting that also in this case the inter individual variability plays a major role. This evidence concerns the gene ABCB1 and Alzheimer disease.