AD may have different clinical presentations depending on the area where the neurodegeneration starts first. The more frequent region is the medial temporal lobe, affecting the hippocampus but there are variants starting in the frontal lobe (frontal AD) and parieto-occipital (posterior AD).
Analyses of cortical thickness patterns support the hypothesis that different clinical presentations of AD represent points in a phenotypic spectrum of neuroanatomical variation (Ridway).
However, serum anti-Aβ IgG1 and IgG3 antibodies differ between distinct forms of AD. Its significance is discussed for possible implications as immune effectors in the specific pathophysiology of AD variants (Dorothée).