However, the trend of reduced BDNF plasma concentration in subjects with AD diagnosis, compared to individuals with MCI, was confirmed by comparing the smaller group of MCI subjects from the previous study by Domitrovic Spudic et al. [56] and the AD group from the present study (U = 5468.00; p = 0.020), and by comparing AD subjects from our former study with MCI group in this study (U = 10,155.00; p < 0.001). The gene discussed is BDNF; the disease is Alzheimer disease.