Subtypes of Neuropsychiatric Symptoms Suggestive of Certain Brain Location, Pathology, or Gene Mutation in FTD
Some neuropsychiatric symptom clusters can suggest distinctive pathologies.
FUS pathology (but not FUS mutation) is characterized by a distinct behavioral profile consisting of very young-onset dementia (before 45 years) with prominent obsessionality, repetitive behaviors and rituals, social withdrawal and lack of engagement, hyperorality with pica, and marked stimulus-bound behavior including utilization behavior. Imaging shows striatal atrophy and there is no strong family history .
C9orf72 mutations are suggested by the association of psychotic symptoms, complex repetitive behaviors (linked to a mono-delusion or an obsessive-compulsive disorder), and the presence of MND in the patient or family members. Negative signs include the absence of early apathy and preference for sweet food despite increased appetite or gluttony .
Patients with a prominent right temporal lobe atrophy are characterized by hyper-religiosity, visual hallucinations, and cross modal sensory experiences . In addition to the behavioral disorders of FTD, they can display episodic memory impairment, visual disorientation, prosopagnosia, and unexplained somatic complaints.