Dataset Information

Posterior Cortical Atrophy phenotype in a GBA N370S mutation carrier: a case report.

ABSTRACT:

Background

Glucocerebrosidase (GBA) heterozygous variants are the most important genetic risk factor for the development of alpha-synucleinopathies (i.e., Parkinson's disease and Dementia with Lewy Bodies). Herein, we report for the first time on a patient with a clinical diagnosis of Posterior Cortical Atrophy, carrier of the common GBA heterozygous variant N370S (c.1226A?>?G).

Case presentation

A 44-year-old woman with positive familial history for Dementia with Lewy Bodies disclosed three related signs characterizing the Balint's syndrome: ocular apraxia, optic ataxia and simultanagnosia. Over 2-year follow up, overt gaze apraxia (psychic paralysis of gaze) appeared leading to functional blindness. Given her young age at onset and positive familial history, she underwent a next-generation-sequencing (NGS) based screening of a panel of 32 genes related to neurodegenerative conditions within the ANAMNESYS (An origiNal Approach to study faMiliarity in NEurodegenerative SYndromeS) study. NGS demonstrated the N370S variant in the GBA gene (rs76763715), confirmed by Sanger sequencing. This is a relatively common variant, with predicted mild impact, already reported to occur in 2.4% of PD Italian patients; however, neither this nor other GBA variants have ever been reported to date in patients with Posterior Cortical Atrophy. Glucocerebrosidase activity was investigated and found to be significantly reduced (4.72?nmol/h/mg) compared to healthy controls as well as patients affected by neurodegenerative diseases, further supporting pathogenicity of the GBA variant.

Conclusions

We report on a patient with a clinical diagnosis of Posterior Cortical Atrophy, carrier of the GBA heterozygous variant N370S (c.1226A?>?G; p.Asn409Ser) determining reduced GCase activity. This report also confirms the role of NGS-based targeted gene analysis in detecting peculiar clinical phenotypes associated with known pathogenic mutations and reinforces the knowledge that carriers of genetic variants often present phenotypic overlaps across different neurodegenerative syndromes, highlighting the limitations of current clinical diagnostic criteria in defining boundaries between distinct conditions and the difficulties of clinicians in reaching the best clinical diagnosis.

SUBMITTER: Picillo M

PROVIDER: S-EPMC7802182 | biostudies-literature | 2021 Jan

REPOSITORIES: biostudies-literature

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Publications

Posterior Cortical Atrophy phenotype in a GBA N370S mutation carrier: a case report.

Picillo Marina M Scannapieco Sara S Iavarone Alessandro A Ginevrino Monia M Valente Enza Maria EM Barone Paolo P

BMC neurology 20210112 1

<h4>Background</h4>Glucocerebrosidase (GBA) heterozygous variants are the most important genetic risk factor for the development of alpha-synucleinopathies (i.e., Parkinson's disease and Dementia with Lewy Bodies). Herein, we report for the first time on a patient with a clinical diagnosis of Posterior Cortical Atrophy, carrier of the common GBA heterozygous variant N370S (c.1226A > G).<h4>Case presentation</h4>A 44-year-old woman with positive familial history for Dementia with Lewy Bodies disc ...[more]

PMID: 33435912

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Project description:Although Alzheimer's disease presents homogeneous histopathology, it causes several clinical phenotypes depending on brain regions involved. Beside the most abundant memory variant, several atypical variants exist. Among them posterior cortical atrophy (PCA) is associated with severe visuospatial/visuoperceptual deficits in the absence of significant primary ocular disease. Here, we report for the first time a case of Capgras delusion-a delusional misidentification syndrome, where patients think that familiar persons are replaced by identical "doubles" or an impostor-in a patient with PCA. The 57-year-old female patient was diagnosed with PCA and developed Capgras delusion 8 years after first symptoms. The patient did not recognize her husband, misidentified him as a stranger, and perceived him as a threat. Such misidentifications did not happen for other persons. Events could be interrupted by reassuring the husband's identity by the patient's female friend or children. We applied in-depth multimodal neuroimaging phenotyping and used single-subject voxel-based morphometry to identify atrophy changes specifically related to the development of the Capgras delusion. The latter, based on structural T1 magnetic resonance imaging, revealed progressive gray matter volume decline in occipital and temporoparietal areas, involving more the right than the left hemisphere, especially at the beginning. Correspondingly, the right fusiform gyrus was already affected by atrophy at baseline, whereas the left fusiform gyrus became involved in the further disease course. At baseline, glucose hypometabolism as measured by positron emission tomography (PET) with F18-fluorodesoxyglucose (FDG-PET) was evident in the parietooccipital cortex, more pronounced right-sided, and in the right frontotemporal cortex. Amyloid accumulation as assessed by PET with F18-florbetaben was found in the gray matter of the neocortex indicating underlying Alzheimer's disease. Appearance of the Capgras delusion was related to atrophy in the right posterior cingulate gyrus/precuneus, as well as right middle frontal gyrus/frontal eye field, supporting right frontal areas as particularly relevant for Capgras delusion. Atrophy in these regions respectively might affect the default mode and dorsal attention networks as shown by meta-analytical co-activation and resting state functional connectivity analyses. This case elucidates the brain-behavior relationship in PCA and Capgras delusion.

Project description:BackgroundPosterior cortical atrophy (PCA) is typically considered to be a visual syndrome, primarily characterised by progressive impairment of visuoperceptual and visuospatial skills. However, patients commonly describe early difficulties with word retrieval. This paper details the first systematic analysis of linguistic function in PCA. Characterising and quantifying the aphasia associated with PCA is important for clarifying diagnostic and selection criteria for clinical and research studies.Methods15 patients with PCA, seven patients with logopenic/phonological aphasia (LPA) and 18 age matched healthy participants completed a detailed battery of linguistic tests evaluating auditory input processing, repetition and working memory, lexical and grammatical comprehension, single word retrieval and fluency, and spontaneous speech.ResultsRelative to healthy controls, PCA patients exhibited language impairments across all of the domains examined, but with anomia, reduced phonemic fluency and slowed speech rate the most prominent deficits. PCA performance most closely resembled that of LPA patients on tests of auditory input processing, repetition and digit span, but was relatively stronger on tasks of comprehension and spontaneous speech.ConclusionsThe study demonstrates that in addition to the well reported degradation of vision, literacy and numeracy, PCA is characterised by progressive oral language dysfunction with prominent word retrieval difficulties. Overlap in the linguistic profiles of PCA and LPA, which are both most commonly caused by Alzheimer's disease, further emphasises the notion of a phenotypic continuum between typical and atypical manifestations of the disease. Clarifying the boundaries between Alzheimer's disease phenotypes has important implications for diagnosis, clinical trial recruitment and investigations into biological factors driving phenotypic heterogeneity in Alzheimer's disease. Rehabilitation strategies to ameliorate the phonological deficit in PCA are required.

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Project description:ObjectivesTo investigate the global cortical and regional quantitative features of cortical neural architecture in the brains of patients with posterior cortical atrophy (PCA) and typical Alzheimer's disease (tAD) compared with elderly healthy controls (HC).MethodsA novel diffusion MRI method, that has been shown to correlate with minicolumnar organization changes in the cerebral cortex, was used as a surrogate of neuropathological changes in dementia. A cohort of 15 PCA patients, 23 tAD and 22 healthy elderly controls (HC) were enrolled to investigate the changes in cortical diffusivity among groups. For each subject, 3 T MRI T1-weighted images and diffusion tensor imaging (DTI) scans were analysed to extract novel cortical DTI derived measures (AngleR, PerpPD and ParlPD). Receiver operating characteristics (ROC) curve analysis and the area under the curve (AUC) were used to assess the group discrimination capability of the method.ResultsThe results showed that the global cortical DTI derived measures were able to detect differences, in both PCA and tAD patients compared to healthy controls. The AngleR was the best measure to discriminate HC from tAD (AUC?=?0.922), while PerpPD was the best measure to discriminate HC from PCA (AUC?=?0.961). Finally, the best global measure to differentiate the two patient groups was ParlPD (AUC?=?0.771). The comparison between PCA and tAD patients revealed a different pattern of damage within the AD spectrum and the regional comparisons identified significant differences in key regions including parietal and temporal lobe cortical areas. The best AUCs were shown by PerpPD right lingual cortex (AUC?=?0.856), PerpPD right superior parietal cortex (AUC?=?0.842) and ParlPD right lateral occipital cortex (AUC?=?0.826).ConclusionsDiagnostic group differences were found, suggesting that the new cortical DTI analysis method may be useful to investigate cortical changes in dementia, providing better characterization of neurodegeneration, and potentially aiding differential diagnosis and prognostic accuracy.

Dataset Information

Posterior Cortical Atrophy phenotype in a GBA N370S mutation carrier: a case report.

Background

Case presentation

Conclusions

Publications

Posterior Cortical Atrophy phenotype in a GBA N370S mutation carrier: a case report.

Similar Datasets

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