Introduction

Recent studies have shown that a large hexanucleotide expansion in C9ORF72 is the most common cause of inherited Frontotemporal Lobar Degeneration (FTLD) and Motor Neuron Disease (MND).1 In pathological terms, expansion carriers show a distinctive molecular signature within the dentate gyrus granule cells and CA4 pyramidal cells of the hippocampus and granule cells of the cerebellum characterised by TDP-43-negative, but p62-positive, neuronal cytoplasmic inclusions (NCI).2 Such inclusions contain dipeptide repeat proteins (DPR)2 ,3 generated through non-ATG initiated translation of the expanded region of the gene.4 ,5 On immunohistochemistry, an equivalent pattern of immunostaining is observed employing either antibodies to p62 or DPR, and that p62 immunostaining is an effective tool for identification of pathology associated with the presence of hexanucleotide expansions in C9ORF72.2 ,3 In clinical terms, psychosis is one of the major clinical traits in patients with FTLD and/or …