KLK6 and Alzheimer disease: Results demonstrated that, in patients diagnosed with MCI, there is an association between the variable "developing Dementia with vascular component" and a plasmatic concentration of neurosin higher than 5.25 ng/ml (p < 0.001) as well as an association between the variable "developing AD" and a plasmatic neurosin concentration lower than 5.25 ng/ml (p = 0.004).