TJP1 and Alzheimer disease: The distinct distribution of ZO-1 in the granular layer, as shown in the control skin (n = 3), was replaced by a punctate staining pattern in AD shaves (n = 7), while all AD samples (n = 11) showed additional ZO-1 stainings underneath the granular layer in the spinous layer supporting an impaired TJ barrier (Fig. 3b).