A progranulin gene deletion in frontotemporal lobar degeneration with corticobasal syndrome in a TREDEM case report.

Background: Behavioral variant frontotemporal dementia usually presents with behavioral and personality changes, social disinhibition, apathy, and lack of empathy, and is characterized by atrophy of the frontal and temporal lobes. Corticobasal syndrome is characterized by asymmetrical involuntary movements, rigidity, apraxia, tremor, dystonia, and cortical sensory deficits.

Objective: We present the case of a 59-year-old patient with a frontotemporal presentation and parkinsonism linked to progranulin gene deletion. We also report the clinical workup needed to reach the diagnosis.

Methods: Clinical, neuropsychological, computed tomography, magnetic resonance imaging, ¹⁸F-fluorodeoxyglucose and ¹⁸F-Flutemetamol positron emission tomography (PET), dopamine-transporter-single-photon emission computed tomography imaging, electroencephalography, and genetic evaluations were conducted.

Results: Our patient presented initially with executive and mnesic deficits along with the presence of apathy and loss of autonomy. Subsequently the cognitive deficits became associated with parkinsonian-like movement disorders and apraxia. Structural images showed right onset temporal and insular atrophy, and the PET images demonstrated right frontotemporal hypometabolism and the absence of amyloid in the cortex. The molecular analysis revealed a heterozygous deletion c.813_816delCACT on the GRN gene. This variant has been reported in the literature as pathogenic and associated with autosomal dominant frontotemporal dementia and corticobasal degeneration. Our patient presented different clinical features than those of the members of the families already described. In these families, some patients either presented immediately with motor syndrome with extrapyramidal features, or never developed extrapyramidal signs. Some subjects presented prevalent language dysfunction while others never presented memory disorders.

Conclusions: The clinical case highlights the phenotypic variability of this entity.