title: Psychiatric Presentations of C9orf72 Mutation: What Are the Diagnostic Implications for Clinicians?
abstract: The C9orf72 mutation was identified as the most frequent genetic cause of frontotemporal dementia (FTD). In light of multiple reports of predominant psychiatric presentations of FTD secondary to C9orf72 mutation, the American Neuropsychiatric Association Committee on Research reviewed all studies on psychiatric aspects of this mutation to identify clinically relevant features for diagnosis. The most common psychiatric presentation is psychosis (21%-56%), with delusions, and/or multimodal hallucinations. Other presentations include late-onset mania and depression with cognitive impairment or catatonia. However, the frequency of C9orf72 mutations is low in typical schizophrenia or bipolar disorders (<0.1%). The authors provide clinical guidance on diagnosis and genetic testing.
authors.affiliation: From the Departments of Psychiatry, Neurology & Neurosurgery, Montreal Neurological Institute and McGill University Health Centre, McGill University, Montreal, Quebec, Canada (S.D.); the Department of Psychiatry and Behavioral Sciences, Stanford University Hospital, Palo Alto, Calif. (S.B.); Massachusetts General Hospital, Harvard University, Boston (B.C.D.); and the Department of Behavioural and Clinical Neurosciences, Institute of Cambridge, University of Cambridge (V.V.).
authors.forename: Simon
authors.initials: S
authors.lastname: Ducharme
authors.affiliation: From the Departments of Psychiatry, Neurology & Neurosurgery, Montreal Neurological Institute and McGill University Health Centre, McGill University, Montreal, Quebec, Canada (S.D.); the Department of Psychiatry and Behavioral Sciences, Stanford University Hospital, Palo Alto, Calif. (S.B.); Massachusetts General Hospital, Harvard University, Boston (B.C.D.); and the Department of Behavioural and Clinical Neurosciences, Institute of Cambridge, University of Cambridge (V.V.).
authors.forename: Sepideh
authors.initials: S
authors.lastname: Bajestan
authors.affiliation: From the Departments of Psychiatry, Neurology & Neurosurgery, Montreal Neurological Institute and McGill University Health Centre, McGill University, Montreal, Quebec, Canada (S.D.); the Department of Psychiatry and Behavioral Sciences, Stanford University Hospital, Palo Alto, Calif. (S.B.); Massachusetts General Hospital, Harvard University, Boston (B.C.D.); and the Department of Behavioural and Clinical Neurosciences, Institute of Cambridge, University of Cambridge (V.V.).
authors.forename: Bradford C
authors.initials: BC
authors.lastname: Dickerson
authors.affiliation: From the Departments of Psychiatry, Neurology & Neurosurgery, Montreal Neurological Institute and McGill University Health Centre, McGill University, Montreal, Quebec, Canada (S.D.); the Department of Psychiatry and Behavioral Sciences, Stanford University Hospital, Palo Alto, Calif. (S.B.); Massachusetts General Hospital, Harvard University, Boston (B.C.D.); and the Department of Behavioural and Clinical Neurosciences, Institute of Cambridge, University of Cambridge (V.V.).
authors.forename: Valerie
authors.initials: V
authors.lastname: Voon
mesh_terms: D000073885:C9orf72 Protein / Q000235:genetics*; D006801:Humans; D001523:Mental Disorders / Q000175:diagnosis* / Q000453:epidemiology / Q000235:genetics*; D009154:Mutation; D012955:Societies, Medical
chemical_list: D000073885:C9orf72 Protein; C568651:C9orf72 protein, human
keywords: C9orf72; Frontotemporal Dementia; Genetics; Psychiatry; Psychosis