Phenotype and imaging features associated with APP duplications.

BACKGROUND: APP duplication is a rare genetic cause of Alzheimer disease and cerebral amyloid angiopathy (CAA). We aimed to evaluate the phenotypes of APP duplications carriers. METHODS: Clinical, radiological, and neuropathological features of 43 APP duplication carriers from 24 French families were retrospectively analyzed, and MRI features and cerebrospinal fluid (CSF) biomarkers were compared to 40 APP-negative CAA controls. RESULTS: Major neurocognitive disorders were found in 90.2% symptomatic APP duplication carriers, with prominent behavioral impairment in 9.7%. Symptomatic intracerebral hemorrhages were reported in 29.2% and seizures in 51.2%. CSF Aß42 levels were abnormal in 18/19 patients and 14/19 patients fulfilled MRI radiological criteria for CAA, while only 5 displayed no hemorrhagic features. We found no correlation between CAA radiological signs and duplication size. Compared to CAA controls, APP duplication carriers showed less disseminated cortical superficial siderosis (0% vs 37.5%, p = 0.004 adjusted for the delay between symptoms onset and MRI). Deep microbleeds were found in two APP duplication carriers. In addition to neurofibrillary tangles and senile plaques, CAA was diffuse and severe with thickening of leptomeningeal vessels in all 9 autopsies. Lewy bodies were found in substantia nigra, locus coeruleus, and cortical structures of 2/9 patients, and one presented vascular amyloid deposits in basal ganglia. DISCUSSION: Phenotypes associated with APP duplications were heterogeneous with different clinical presentations including dementia, hemorrhage, and seizure and different radiological presentations, even within families. No apparent correlation with duplication size was found. Amyloid burden was severe and widely extended to cerebral vessels as suggested by hemorrhagic features on MRI and neuropathological data, making APP duplication an interesting model of CAA.

Does a rabbit have feathers or fur? Development of a 42-item semantic memory test (SMT-42).

OBJECTIVE: We present the preliminary study of the 42-item Semantic Memory Test (SMT-42), a test developed to distinguish semantic variant primary progressive aphasia (svPPA) from the other variants: logopenic (lPPA) and nonfluent/agrammatic (naPPA). The test requires the patient to retrieve the conceptual features of items belonging to different lexical categories. METHODS: In the first study, we administered the French version of the SMT-42 to a population of healthy subjects and to patients with svPPA matched to a subgroup of the healthy subjects. In the second study, we administered the SMT-42 to four groups of patients (with svPPA, lPPA, naPPA and Alzheimer's disease [AD], respectively) to study its capacity to differentiate patients suffering from svPPA from the other patients. RESULTS: In the first study, 109 healthy subjects were included, 15 of whom were paired with 15 subjects presenting with svPPA. In the second study, designed to compare groups presenting a primary progressive aphasia variant and AD, 12 subjects with svPPA, 6 with naPPA and 9 with lPPA were included, along with 21 subjects with AD. The subjects presenting a semantic deficit were clearly distinguished from the others by their results on the SMT-42 (svPPA: mean = 30.0 (5.9); lPPA: mean = 37.8 (3.3), d = 1.5, p = 0.002; naPPA: mean = 39.8 (1.9), d = 1.89, p = 0.001; AD: mean = 38.5 (2.4), d = 1.63, p < 0.001); (svPPA: median = 31; lPPA: median = 38, U = 9, p = 0.002; naPPA: median = 40.5, U = 1.5, p = 0.001; AD: median = 39, U = 13.5, p < 0.001). CONCLUSION: The SMT-42 is simple, rapidly administered (3 minutes on average), easily scored and has good sensitivity, and it appears to be an effective tool for semantic screening in routine clinical practice.

Relations between C9orf72 expansion size in blood, age at onset, age at collection and transmission across generations in patients and presymptomatic carriers.

A (GGGGCC)n repeat expansion in C9orf72 gene is the major cause of frontotemporal dementia (FTD) and amyotrophic lateral sclerosis (ALS). The relations between the repeats size and the age at disease onset (AO) or the clinical phenotype (FTD vs. ALS) were investigated in 125 FTD, ALS, and presymptomatic carriers. Positive correlations were found between repeats number and the AO (p < 10e-4) but our results suggested that the association was mainly driven by age at collection (p < 10e-4). A weaker association was observed with clinical presentation (p = 0.02), which became nonsignificant after adjustment for the age at collection in each group. Importantly, repeats number variably expanded or contracted over time in carriers with multiple blood samples, as well as through generations in parent-offspring pairs, conversely to what occurs in several expansion diseases with anticipation at the molecular level. Finally, this study establishes that measure of repeats number in lymphocytes is not a reliable biomarker predictive of the AO or disease outcome in C9orf72 long expansion carriers.

Author Correction: Pathogenic p62/SQSTM1 mutations impair energy metabolism through limitation of mitochondrial substrates.

A correction has been published and is linked to the HTML and PDF versions of this paper. The error has not been fixed in the paper.

Cerebral microbleeds and CSF Alzheimer biomarkers in primary progressive aphasias.

OBJECTIVE: To reveal the prevalence and localization of cerebral microbleeds (CMBs) in the 3 main variants of primary progressive aphasia (PPA) (logopenic, semantic, and nonfluent/agrammatic), to identify the relationship with underlying Alzheimer pathology, and to explore whether CMBs contribute to language breakdown. METHODS: We used a cross-sectional design in a multicenter cohort of 82 patients with PPA and 19 similarly aged healthy controls. MRI allowed for rating CMBs (2-dimensional gradient recalled echo T2*, susceptibility weighted imaging sequences) and white matter hyperintensities. CSF Alzheimer disease biomarker analyses available in 63 of the 82 patients provided the stratification of PPA into subgroups with patients who had or did not have probable underlying Alzheimer pathology. RESULTS: The prevalence of CMBs was higher in patients with PPA (28%) than in controls (16%). They were more prevalent in logopenic PPA (50%) than in semantic PPA (18%) and nonfluent/agrammatic PPA (17%). The localization of CMBs was mainly lobar (81%) with no difference between the PPA variants. CMBs were more frequent in PPA patients with positive than with negative CSF Alzheimer disease biomarkers (67% vs 20%). Patients with and without lobar CMBs had similar volumes of white matter hyperintensities. Language and general cognitive impairment in PPA was unrelated to CMB rates. CONCLUSIONS: CMB prevalence in PPA is higher than in healthy controls. CMBs were most prevalent in the logopenic variant, were related to underlying Alzheimer pathology, and did not affect the language/cognitive impairment. Our findings also suggest that CMB detection with MRI contributes to PPA variant diagnosis, especially of logopenic PPA, and provides an estimator of the underlying neuropathology.

Pathogenic p62/SQSTM1 mutations impair energy metabolism through limitation of mitochondrial substrates.

Abnormal mitochondrial function has been found in patients with frontotemporal dementia (FTD) and amyotrophic lateral sclerosis (ALS). Mutations in the p62 gene (also known as SQSTM1) which encodes the p62 protein have been reported in both disorders supporting the idea of an ALS/FTD continuum. In this work the role of p62 in energy metabolism was studied in fibroblasts from FTD patients carrying two independent pathogenic mutations in the p62 gene, and in a p62-knock-down (p62 KD) human dopaminergic neuroblastoma cell line (SH-SY5Y). We found that p62 deficiency is associated with inhibited complex I mitochondrial respiration due to lack of NADH for the electron transport chain. This deficiency was also associated with increased levels of NADPH reflecting a higher activation of pentose phosphate pathway as this is accompanied with higher cytosolic reduced glutathione (GSH) levels. Complex I inhibition resulted in lower mitochondrial membrane potential and higher cytosolic ROS production. Pharmacological activation of transcription factor Nrf2 increased mitochondrial NADH levels and restored mitochondrial membrane potential in p62-deficient cells. Our results suggest that the phenotype is caused by a loss-of-function effect, because similar alterations were found both in the mutant fibroblasts and the p62 KD model. These findings highlight the implication of energy metabolism in pathophysiological events associated with p62 deficiency.

Symptomatic treatments in Alzheimer's disease in 2016: a study from Memory centers in France.

Cholinesterase inhibitors and memantine are used from 15 years, in Alzheimer's disease. Benefits have been demonstrated according to cognition, activities of daily living, affective symptoms and behavior, and global impression of change. The aims of this paper are: 1) to describe how these treatments are used in France with a sample survey managed by the national federation of the french CMRR; 2) to study data about efficacy, safety, medicoeconomic impacts and how they are used in Europe.

Ugly aesthetic perception associated with emotional changes in experience of art by behavioural variant of frontotemporal dementia patients.

The aesthetic experience through art is a window into the study of emotions. Patients with behavioural variant of frontotemporal dementia (bvFTD) have early alteration of emotional processing. A new appreciation of art has been reported in some of these patients. We designed a computerized task using 32 abstract paintings that allowed us to investigate the integrity of patients' emotions when viewing the artwork. We evaluated both conscious and explicit appraisal of emotions [aesthetic judgment (beautiful/ugly), emotional relevance (affected or not by the painting), emotional valence (pleasant/unpleasant), emotional reaction (adjective choice) and arousal] and unconscious processing. Fifteen bvFTD patients and 15 healthy controls were included. BvFTD patients reported that they were "little touched" by the paintings. Aesthetic judgment was very different between the two groups: the paintings were considered ugly (negative aesthetic bias) and unpleasant (negative emotional bias) more often by the patients than by controls. Valence and aesthetic judgments correlated in both groups. In addition, there was a positive bias in the implicit task and for explicit emotional responses. Patients frequently chose the word "sad" and rarely expressed themselves with such adjectives as "happy". Our results suggest that bvFTD patients can give an aesthetic judgment, but present abstraction difficulties, as spectators, resulting from impairments in the cognitive processes involved. They also have difficulties in terms of emotional processes with the loss of the ability to feel the emotion per se (i.e., to feel an emotion faced with art) linked to behaviour assessment. This cognitive approach allows us to better understand which spectators are bvFTD patients and to show interactions between emotions and behavioural disorders.

The Behavioral and Cognitive Executive Disorders of Stroke: The GREFEX Study.

BACKGROUND: Many studies have highlighted the high prevalence of executive disorders in stroke. However, major uncertainties remain due to use of variable and non-validated methods. The objectives of this study were: 1) to characterize the executive disorder profile in stroke using a standardized battery, validated diagnosis criteria of executive disorders and validated framework for the interpretation of neuropsychological data and 2) examine the sensitivity of the harmonization standards protocol proposed by the National Institute of Neurological Disorders and Stroke and Canadian Stroke Network (NINDS-CSN) for the diagnosis of Vascular Cognitive Impairment. METHODS: 237 patients (infarct: 57; cerebral hemorrhage: 54; ruptured aneurysm of the anterior communicating artery (ACoA): 80; cerebral venous thrombosis (CVT): 46) were examined by using the GREFEX battery. The patients' test results were interpreted with a validated framework derived from normative data from 780 controls. RESULTS: Dysexecutive syndrome was observed in 88 (55.7%; 95%CI: 48-63.4) out of the 156 patients with full cognitive and behavioral data: 40 (45.5%) had combined behavioral and cognitive syndromes, 29 (33%) had a behavioral disorder alone and 19 (21.6%) had a cognitive syndrome alone. The dysexecutive profile was characterized by prominent impairments of initiation and generation in the cognitive domain and by hypoactivity with disinterest and anticipation loss in the behavioral domain. Cognitive impairment was more frequent (p = 0.014) in hemorrhage and behavioral disorders were more frequent (p = 0.004) in infarct and hemorrhage. The harmonization standards protocol underestimated (p = 0.007) executive disorders in CVT or ACoA. CONCLUSIONS: This profile of executive disorders implies that the assessment should include both cognitive tests and a validated inventory for behavioral dysexecutive syndrome. Initial assessment may be performed with a short cognitive battery, such as the harmonization standards protocol. However, administration of a full cognitive battery is required in selected patients.

Lateral Temporal Lobe: An Early Imaging Marker of the Presymptomatic GRN Disease?

The preclinical stage of frontotemporal lobar degeneration (FTLD) is not well characterized. We conducted a brain metabolism (FDG-PET) and structural (cortical thickness) study to detect early changes in asymptomatic GRN mutation carriers (aGRN+) that were evaluated longitudinally over a 20-month period. At baseline, a left lateral temporal lobe hypometabolism was present in aGRN+ without any structural changes. Importantly, this is the first longitudinal study and, across time, the metabolism more rapidly decreased in aGRN+ in lateral temporal and frontal regions. The main structural change observed in the longitudinal study was a reduction of cortical thickness in the left lateral temporal lobe in carriers. A limit of this study is the relatively small sample (n = 16); nevertheless, it provides important results. First, it evidences that the pathological processes develop a long time before clinical onset, and that early neuroimaging changes might be detected approximately 20 years before the clinical onset of disease. Second, it suggests that metabolic changes are detectable before structural modifications and cognitive deficits. Third, both the baseline and longitudinal studies provide converging results implicating lateral temporal lobe as early involved in GRN disease. Finally, our study demonstrates that structural and metabolic changes could represent possible biomarkers to monitor the progression of disease in the presymptomatic stage toward clinical onset.

DAPHNE: A New Tool for the Assessment of the Behavioral Variant of Frontotemporal Dementia.

BACKGROUND: The diagnosis of behavioral variant of frontotemporal dementia (bvFTD) relies primarily on clinical features and remains challenging. The specificity of the recently revised criteria can be disappointing, justifying development of new clinical tools. OBJECTIVE: We produced a behavioral inventory named DAPHNE. This scale (adapted from Rascovsky's criteria) explores six domains: disinhibition, apathy, perseverations, hyperorality, personal neglect and loss of empathy. It is composed of ten items (five answer categories). The aim was (1) to assess the validity and reliability of DAPHNE and (2) to evaluate its contribution in differentiating patients. METHODS: Two scores were computed: DAPHNE-6 (screening) from the six domains and DAPHNE-40 (diagnosis) from the ten items. Reliability and reproducibility were assessed. External validity was studied with the Frontal Behavioral Inventory (FBI) and the Frontotemporal Behavioral Scale (FBS). Finally, the diagnostic performance of DAPHNE was compared to revised criteria, FBI and FBS. RESULTS: DAPHNE was administered to the caregivers of 89 patients, 36 with bvFTD, 22 with Alzheimer's disease, 15 with progressive supranuclear palsy and 16 with bipolar disorder. Reliability and reproducibility were excellent, as was external validity. DAPHNE-6 allowed bvFTD diagnosis (score ≥4) with a sensitivity of 92%, while DAPHNE-40 (score ≥15) had a specificity of 92%. CONCLUSION: We demonstrate excellent psychometric features for DAPHNE. This quick tool could help for both diagnosing and screening bvFTD.

A phenotype of atypical apraxia of speech in a family carrying SQSTM1 mutation.

SQSTM1 mutations, coding for the p62 protein, were identified as a monogenic cause of Paget disease of bone and of amyotrophic lateral sclerosis. More recently, SQSTM1 mutations were identified in few families with frontotemporal dementia. We report a new family carrying SQSTM1 mutation and presenting with a clinical phenotype of speech apraxia or atypical behavioral disorders, associated with early visuo-contructional deficits. This study further supports the implication of SQSTM1 in frontotemporal dementia, and enlarges the phenotypic spectrum associated with SQSTM1 mutations.

[Frontal variant of frontotemporal dementia]. / La variante frontale de dégénérescence frontotemporale.

The behavioral variant of frontotemporal dementia (bvFTD), characterized by early behavioral disorders, is a rare disease (about 5.000 cases in France). Diagnostic criteria have been revised in 2011 and propose three levels of diagnostic probability. However, it still could be difficult to discriminate FTD from other cerebral affections or psychiatric diseases. Genetic and molecular research has greatly expanded during the past fifteen years. About ten mutations have been discovered, bringing to describe particular phenotypes. To date, there is no curative treatment. Memantine had aroused some hope but is now abandoned. Inhibitors of serotonine recapture often permit to temporarily reduce behavioral troubles. But the caregiver's burden is high. The evolution of the bvFTD is faster than that of AD, particularly when associated with motor neuron disease (15% of cases). The therapeutic hope relies today on potential disease modifying drugs which could ensue from genetic discoveries.

DCTN1 mutation analysis in families with progressive supranuclear palsy-like phenotypes.

IMPORTANCE: Progressive supranuclear palsy (PSP) is usually sporadic, but few pedigrees with familial clustering of PSP-like phenotypes have been described. Occasionally, MAPT, C9ORF72, and TARDBP mutations have been identified. OBJECTIVE: To analyze the DCTN1 gene in 19 families with a clinical phenotype of PSP (PSP-like phenotype). DESIGN, SETTING, AND PARTICIPANTS: Sequencing of the DCTN1 gene in familial forms of PSP at a referral center among 21 patients with familial PSP-like phenotypes. In addition, 8 patients and relatives from a family carrying a DCTN1 mutation were evaluated. MAIN OUTCOMES AND MEASURES: Identification of the DCTN1 mutation and clinical description of DCTN1 mutation carriers. RESULTS: We identified a DCTN1 mutation in a large family characterized by high intrafamilial clinical phenotype variability. Two patients had PSP-like phenotypes with dystonia, vertical gaze slowness, dysexecutive syndrome, predominant axial rigidity, and midbrain atrophy on brain magnetic resonance imaging. The other patients manifested Perry syndrome, isolated parkinsonism, or a predominant behavioral variant of frontotemporal dementia. CONCLUSIONS AND RELEVANCE: Mutations of the DCTN1 gene have been previously associated with amyotrophic lateral sclerosis and with Perry syndrome, a rare autosomal dominant disorder characterized by weight loss, parkinsonism, central hypoventilation, and psychiatric disturbances. Our study demonstrates that DCTN1 mutations should be searched for in patients with clinical PSP-like phenotypes and a behavioral variant of frontotemporal dementia, especially when a familial history of dementia, psychiatric disturbances, associated parkinsonism, or an autosomal dominant disorder is present.

C9ORF72 repeat expansions in the frontotemporal dementias spectrum of diseases: a flow-chart for genetic testing.

Frontotemporal dementia (FTD) refers to a disease spectrum including the behavioral variant FTD (bvFTD), primary progressive aphasia (PPA), progressive supranuclear palsy/corticobasal degeneration syndrome (PSP/CBDS), and FTD with amyotrophic lateral sclerosis (FTD-ALS). A GGGGCC expansion in C9ORF72 is a major cause of FTD and ALS. C9ORF72 was analyzed in 833 bvFTD, FTD-ALS, PPA, and PSP/CBDS probands; 202 patients from 151 families carried an expansion. C9ORF72 expansions were much more frequent in the large subgroup of patients with familial FTD-ALS (65.9%) than in those with pure FTD (12.8%); they were even more frequent than in familial pure ALS, according to estimated frequencies in the literature (23-50%). The frequency of carriers in non-familial FTD-ALS (12.7%) indicates that C9ORF72 should be analyzed even when family history is negative. Mutations were detected in 6.8% of PPA patients, and in 3.2% of patients with a clinical phenotype of PSP, thus enlarging the phenotype spectrum of C9ORF72. Onset was later in C9ORF72 (57.4 years, 95%CI: 55.9-56.1) than in MAPT patients (46.8, 95%CI: 43.0-50.6; p = 0.00001) and the same as in PGRN patients (59.6 years; 95%CI: 57.6-61.7; p = 0.4). ALS was more frequent in C9ORF72 than in MAPT and PGRN patients; onset before age 50 and parkinsonism were indicative of MAPT mutations, whereas hallucinations were indicative of PGRN mutations; prioritization of genetic testing is thus possible. Penetrance was age- and gender-dependent: by age 50, 78% of male carriers were symptomatic, but only 52% of females. This can also guide genetic testing and counseling. A flowchart for genetic testing is thus proposed.

Prospective evaluation of behavioral scales in the behavioral variant of frontotemporal dementia.

BACKGROUND: The Neuropsychiatric Inventory (NPI) and the Frontal Behavioral Inventory (FBI) are widely used in patients with the behavioral variant of frontotemporal dementia (bvFTD). Yet, few data are available on the long-term relevance of these scales. MATERIAL AND METHODS: Based on a bvFTD population that participated in the Memantine Clinical Trial (NCT00200538), we studied the evolution and correlation between scores obtained on behavioral scales (NPI and FBI), cognitive scales [Mini-Mental State Examination (MMSE) and Mattis Dementia Rating Scale (MDRS)] and a burden scale [Zarit Burden Inventory (ZBI)]. The assessments were performed at 1 year in 41 patients and at 2 years in 23 patients who agreed to participate in this open-label study. RESULTS: The 2-year scores obtained on the FBI were significantly higher than the scores at inclusion while those obtained on the NPI did not change. There were significant correlations between the FBI, and the MDRS and MMSE, especially regarding the negative items. The ZBI correlated with behavioral scales at all stages for positive items. CONCLUSIONS: This study based on a large population shows that the FBI is a better tool than the NPI for the long-term assessment of bvFTD patients. Moreover, the FBI allows a distinction to be made between behavioral disturbances that involve cognitive functions from those which have an important impact on caregiver burden.

Validation of AclarusDx™, a blood-based transcriptomic signature for the diagnosis of Alzheimer's disease.

Biomarkers have gained an increased importance in the past years in helping physicians to diagnose Alzheimer's disease (AD). This study was designed to identify a blood-based, transcriptomic signature that can differentiate AD patients from control subjects. The performance of the signature was then evaluated for robustness in an independent blinded sample population. RNA was extracted from 177 blood samples (90 AD patients and 87 controls) and gene expression profiles were generated using the human Genome-Wide Splice Array™. These profiles were used to establish a signature to differentiate AD patients from controls. Subsequently, prediction results were optimized by establishing grey zone boundaries that discount prediction scores near the disease status threshold. Signature validation was then performed on a blinded independent cohort of 209 individuals (111 AD and 98 controls). The AclarusDx™ signature consists of 170 probesets which map to 136 annotated genes, a significant number of which are associated with inflammatory, gene expression, and cell death pathways. Additional signature genes are known to interact with pathways involved in amyloid and tau metabolism. The validation sample set, after removal of 45 individuals with prediction profile scores within the grey zone, consisted of 164 subjects. The AclarusDx™ performance on this validation cohort had a sensitivity of 81.3% (95% CI: [73.3%; 89.3%]); and a specificity of 67.1% (95% CI: [56.3%; 77.9%]). AclarusDx™ is a non-invasive blood-based transcriptomic test that, in combination with standard assessments, can provide physicians with objective information to support the diagnosis of AD.

Value of neuropsychological testing, imaging, and CSF biomarkers for the differential diagnosis and prognosis of clinically ambiguous dementia.

The objective of this study was to examine the diagnostic accuracy of imaging and CSF biomarkers in clinically ambiguous dementia (CAD). 69 patients were prospectively followed. The endpoint was clinical diagnosis at follow-up of 24 months based upon existing criteria. Medial temporal lobe atrophy score on MRI, distinctive patterns on 99 mTc-HMPAO-SPECT, and CSF levels of amyloid-ß peptide, total tau protein, and P-tau181P were used together with neuropsychological testing to assess Se (sensitivity) and Sp (specificity) of separate and combined markers. 60 patients reached the endpoint. A definite diagnosis was achieved in 48 patients. CSF biomarkers had a Sp of 71% and a Se of 100% for Alzheimer's disease (AD) diagnosis. Sp increased to 88% and 93% when MRI and MRI + SPECT were combined, at the expense of Se. CSF biomarkers levels also provided clues to frontotemporal (FTD) or vascular dementias (VaD) diagnosis when situated in an intermediate range between normal and pathological values. MRI and SPECT contributed mostly to the diagnosis of VaD (Se 88%, Sp 75%) and FTD (Se 73%, Sp 78%), respectively. Initial neuropsychological testing had a poor diagnostic accuracy, except for a neuropsychiatric inventory score >40 for the diagnosis of FTD (Se 73%, Sp 84%). Independent of the clinical diagnosis, medial temporal lobe atrophy and total-tau were best correlated with cognitive decline at 2 years. In conclusion, CSF biomarkers efficiently predict evolution toward an AD phenotype in CAD. Imaging biomarkers mostly contribute to the differential diagnosis between non-AD dementias. Initial neuropsychological testing was poorly contributive in CAD diagnosis.

A genome-wide study reveals rare CNVs exclusive to extreme phenotypes of Alzheimer disease.

Studying rare extreme forms of Alzheimer disease (AD) may prove to be a useful strategy in identifying new genes involved in monogenic determinism of AD. Amyloid precursor protein (APP), PSEN1, and PSEN2 mutations account for only 85% of autosomal dominant early-onset AD (ADEOAD) families. We hypothesised that rare copy number variants (CNVs) could be involved in ADEOAD families without mutations in known genes, as well as in rare sporadic young-onset AD cases. Using high-resolution array comparative genomic hybridisation, we assessed the presence of rare CNVs in 21 unrelated ADEOAD cases, having no alteration on known genes, and 12 sporadic AD cases, with an age of onset younger than 55 years. The analysis revealed the presence of 7 singleton CNVs (4 in ADEOAD and 3 in sporadic cases) absent in 1078 controls and 912 late-onset AD cases. Strikingly, 4 out of 7 rearrangements target genes (KLK6, SLC30A3, MEOX2, and FPR2) encoding proteins that are tightly related to amyloid-ß peptide metabolism or signalling. Although these variants are individually rare and restricted to particular subgroups of patients, these findings support the causal role, in human pathology, of a set of genes coding for molecules suspected for a long time to modify Aß metabolism or signalling, and for which animal or cellular models have already been developed.

Memantine in behavioral variant frontotemporal dementia: negative results.

We tested the efficacy and tolerability of one-year treatment with memantine (10 mg bid) in behavioral variant frontotemporal dementia (bvFTD). BvFTD patients aged 45 to 75 years, with a Mini-Mental Status Examination (MMSE) score ≥19, were enrolled in a national, randomized, double-blind, placebo-controlled (DBPC), Phase II trial. The primary endpoint was the CIBIC-Plus (Clinician's Interview-Based Impression of Change Plus Caregiver Input). The secondary endpoints included: Neuropsychiatric Inventory (NPI), Frontal Behavioral Inventory (FBI), Mattis Dementia Rating Scale (MDRS), MMSE, Disability Assessment for Dementia (DAD), and the Zarit Burden Inventory (ZBI). Forty-nine patients were analyzed. At baseline, mean age was 65.6 years and mean MMSE was 25.0 (range: 19-30). On the CIBIC-Plus, 52 weeks after baseline, there were no significant differences between the memantine group (n = 23) and the placebo group (n = 26); p = 0.4458; however, 10 patients had worsened in the memantine group versus 17 in the placebo group. For the secondary endpoints there were no differences in the evolution of score between the memantine group and the placebo group (MMSE, p = 0.63); (MDRS, p = 0.95); (NPI, p = 0.25); (ZBI, p = 0.43); (DAD, p = 0.10) except for the FBI score, which was lower in the memantine group (p = 0.0417). Memantine was well-tolerated. This is the first DBPC trial in a large group of bvFTD patients involving neuroprotective treatment. A multinational study with a larger number of patients is now needed in order to verify the results of our study. The trial is registered with ClinicalTrials.gov; number NCT 00200538.