The bvFTD phenocopy syndrome: a clinicopathological report

Devenney, Emma; Forrest, Shelley L.; Xuereb, John H.; Kril, Jillian J.; Hodges, John R.

doi:10.1136/jnnp-2015-312826

Cited by 24 publications

(25 citation statements)

References 5 publications

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“…So far, only four patients with phFTD underwent autopsy [13, 35]. Two phFTD cases with behavioral disorders, mild dysexecutive function, and unchanged neuropsychological testing during follow-up (5 and 10 years) did not have FTLD pathology on postmortem pathological exam [35].…”

Section: Resultsmentioning

confidence: 99%

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Phenocopy syndrome of behavioral variant frontotemporal dementia: a systematic review

et al. 2019

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Background The phenocopy syndrome of behavioral variant of frontotemporal dementia (phFTD) refers to patients presenting with neuropsychiatric symptoms mimicking the behavioral variant frontotemporal dementia (bvFTD), but lacking frontotemporal atrophy/hypometabolism on neuroimaging and not evolving to dementia during the follow-up. It is important to recognize phFTD for clinical and research purposes. Objective The aim of this study was to perform a systematic review of the available literature on phFTD taking into account its clinical, cognitive, imaging, genetic, and pathological features. Methods and results We searched for the following terms in two electronic databases (PubMed and Scopus): “frontotemporal dementia and slowly progressive,” “frontotemporal dementia and phenocopy,” “frontotemporal dementia and non-progressive,” “frontotemporal dementia and benign progression,” and “frontotemporal dementia and benign.” We did not include review articles. Papers had to be written in English, French, Portuguese, or Spanish. Overall, 235 studies were retrieved in the initial search. A total of 31 studies composed the final selection, comprising 292 patients. Patients with phFTD are predominantly male and have no major cognitive deficits, with globally preserved executive functions and episodic memory. Some cases ( n = 7) of slowly progressive FTD have been associated with C9orf72 genetic expansion. There are only four reports of phFTD neuropathological data, with two patients with no neurodegenerative findings and two with frontotemporal lobar degeneration with ubiquitin-positive inclusions. Conclusion The neurobiological underpinnings of phFTD remain unknown. It is controversial whether phFTD belongs to the FTD spectrum. Studies with biomarkers and pathological data are needed to solve the phFTD conundrum.

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Section: Resultsmentioning

confidence: 99%

“…There are only four phFTD reports with postmortem neuropathological assessment. No FTLD pathology was found in two cases [35], while FTLD pathology was documented in two patients [13, 36].…”

Section: Discussionmentioning

confidence: 99%

Phenocopy syndrome of behavioral variant frontotemporal dementia: a systematic review

et al. 2019

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“…On a clinical level, these patients present with cognitive and behavioural changes, that are identical to the deficits seen in probable bvFTD cases, yet do not show significant brain atrophy [ 6 , 16 ]. Furthermore, a previous clinicopathological study found that 2 phenocopy cases did not have FTLD pathology at autopsy [ 17 ]. While it is possible that the phenocopy syndrome represents a late onset decompensated developmental disorder in the Asperger-Autism spectrum, it remains to be proven.…”

Section: Discussionmentioning

confidence: 99%

The behavioural variant frontotemporal dementia phenocopy syndrome is a distinct entity - evidence from a longitudinal study

et al. 2018

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BackgroundThis study aimed to i) examine the frequency of C9orf72 expansions in a cohort of patients with the behavioural variant frontotemporal dementia (bvFTD) phenocopy syndrome, ii) observe outcomes in a group of phenocopy syndrome with very long term follow-up and iii) compare progression in a cohort of patients with the phenocopy syndrome to a cohort of patients with probable bvFTD.MethodsBlood was obtained from 16 phenocopy cases. All met criteria for possible bvFTD and were labeled as phenocopy cases if they showed no functional decline, normal cognitive performance on the Addenbrooke’s Cognitive Examination-Revised (ACE-R) and a lack of atrophy on brain imaging, over at least 3 years of follow-up. In addition, we obtained very long term follow-up data in 6 cases. A mixed model analysis approach determined the pattern of change in cognition and behaviour over time in phenocopy cases compared to 27 probable bvFTD cases.ResultsAll 16 patients were screened for the C9orf72 expansion that was present in only one (6.25%). Of the 6 cases available for very long-term follow-up (13 - 21 years) none showed progression to frank dementia. Moreover, there was a decrease in the caregiver ratings of behavioural symptoms over time. Phenocopy cases showed significantly slower rates of progression compared to probable bvFTD patients (p < 0.006).ConclusionThe vast majority of patients with the bvFTD phenocopy syndrome remain stable over many years. An occasional patient can harbor the C9orf72 expansion. The aetiology of the remaining cases remains unknown but it appears very unlikely to reflect a neurodegenerative syndrome due to lack of clinical progression or atrophy on imaging.

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“…A series of studies have revealed prognosis markers of this syndrome, notably a lack of atrophy on MRI, normal FDG-PET imaging, normal performance of some cognitive tasks and general preservation of activities of daily living [ 114, 115 ]. Pathological information in the phenocopy syndrome is sparse but one long-term follow-up study of two patients with incidental deaths showed no evidence of FTD at autopsy [ 108 ]. It seems likely that such patients have lifelong personality disorders or cryptic neuropsychiatric disorders rather than a true dementia.…”

Section: Understanding Disease Progression In Ftdmentioning

confidence: 99%

Progress and Challenges in Frontotemporal Dementia Research: A 20-Year Review

Hodges

Piguet

2018

JAD

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The landscape of frontotemporal dementia (FTD) has evolved remarkably in recent years and is barely recognizable from two decades ago. Knowledge of the clinical phenomenology, cognition, neuroimaging, genetics, pathology of the different subtypes of FTD, and their relations to other neurodegenerative conditions, has increased rapidly, due in part, to the growing interests into these neurodegenerative brain conditions. This article reviews the major advances in the field of FTD over the past 20 years, focusing primarily on the work of Frontier, the frontotemporal dementia clinical research group, based in Sydney, Australia. Topics covered include clinical presentations (cognition, behavior, neuroimaging), pathology, genetics, and disease progression, as well as interventions and carer directed research. This review demonstrates the improvement in diagnostic accuracy and capacity to provide advice on genetic risks, prognosis, and outcome. The next major challenge will be to capitalize on these research findings to develop effective disease modifying drugs, which are currently lacking.

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The bvFTD phenocopy syndrome: a clinicopathological report

Cited by 24 publications

References 5 publications

Phenocopy syndrome of behavioral variant frontotemporal dementia: a systematic review

Phenocopy syndrome of behavioral variant frontotemporal dementia: a systematic review

The behavioural variant frontotemporal dementia phenocopy syndrome is a distinct entity - evidence from a longitudinal study

Progress and Challenges in Frontotemporal Dementia Research: A 20-Year Review

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