TREM2 and Alzheimer disease: Some studies have revealed that R47H variation reduced the presence of TREM2 on the surface of immune cells by preventing the maturation194 or by reducing the stability of TREM2.195,196 However, other studies found that R47H variant affected TREM2 function by altering its binding ability rather than expression.192,197,198 R47H mutation also leads to multiple changed in AD pathology.