AT8 immunostaining observed in DS-AD and AD suggested that the Tau immunostaining, at least in the forms that are recognized by the AT8 antibody (phosphorylated Tau at serine 202 and threonine 205) displayed a similar regional distribution to that found with 3H-THK5117 and 3H-MK6240. The gene discussed is MAPT; the disease is Alzheimer disease.