RPTN and Alzheimer disease: Our study has revealed decreased mRNA expression of FLG, FLG2, LOR, CRNN and SPRR3v1 concomitant with increased LELP1, RPTN, HRNR and SPRR1Av1 mRNA levels in AD compared to healthy controls, which is in line with previous findings [15,16,17,21,22,23,24].