GRN and Alzheimer disease: There is some evidence that patients with LPA show impaired single word comprehension with disease progression and the overlapping pattern of anatomical involvement of the temporo-parietal junction in both LPA associated with AD and GRN mutations suggests that this may be a feature of the neuroanatomy rather than the underlying molecular substrate (Beck et al., 2008; Gorno-Tempini et al., 2008; Rabinovici et al., 2008).