Chiara Cupidi

Autosomal Dominant Frontotemporal Lobar Degeneration Due to the C9ORF72 Hexanucleotide Repeat Expansion: Late-Onset Psychotic Clinical Presentation

BACKGROUND A hexanucleotide repeat expansion in the first intron of C9ORF72 has been shown to be responsible for a high number of familial cases of amyotrophic lateral sclerosis or frontotemporal lobar degeneration (FTLD). Atypical presentations have been described, particularly psychosis. METHODS We determined the frequency of the hexanucleotide repeat expansions in a population of 651 FTLD patients and compared the clinical characteristics of carriers and noncarriers. In addition, we genotyped 21 patients with corticobasal syndrome, 31 patients with progressive supranuclear palsy, and 222 control subjects. RESULTS The pathogenic repeat expansion was detected in 39 (6%) patients with FTLD (17 male and 22 female subjects); however, it was not detected in any corticobasal syndrome and progressive supranuclear palsy patients or controls. Twenty-four of 39 carriers had positive family history for dementia and/or amyotrophic lateral sclerosis (61.5%), whereas only 145 of 612 noncarriers had positive family history (23.7%; p<.000001). Clinical phenotypes of carriers included 29 patients with the behavioral variant frontotemporal dementia (bvFTD; 5.2% of all bvFTD cases), 8 with bvFTD/motor neuron disease (32% bvFTD/motor neuron disease cases), 2 with semantic dementia (5.9% of patients with semantic dementia), and none with progressive nonfluent aphasia. The presentation with late-onset psychosis (median age = 63 years) was more frequent in carriers than noncarriers (10/33 vs. 3/37, p = .029), as well as the presence of cognitive impairment at onset (15/33 vs. 5/37; p = .0039). CONCLUSIONS The repeat expansion in C9ORF72 is a common cause of FTLD and often presents with late-onset psychosis or memory impairment.

Hereditary cerebral hemorrhage with amyloidosis associated with the E693K mutation of APP.

OBJECTIVE To report the clinical, genetic, neuroimaging, and neuropathologic studies of patients with the hereditary cerebral hemorrhage with amyloidosis linked to the APP E693K mutation. DESIGN Case series. Clinical details and laboratory results were collected by direct evaluation and previous medical records. DNA analysis was carried out in several affected subjects and healthy individuals. Neuropathologic examination was performed in 2 subjects. SETTING Southern Lombardy, Italy. Patients Individuals with and without amyloidosis in 4 unrelated Italian families (N = 37). Main Outcome Measure Genotype-phenotype relationship. RESULTS The affected individuals presented with recurrent headache and multiple strokes, followed by epilepsy and cognitive decline in most of them. The disease was inherited with an autosomal dominant trait and segregated with the APP E693K mutation. Neuroimaging demonstrated small to large hematomas, subarachnoid bleeding, scars with hemosiderin deposits, small infarcts, and leukoaraiosis. Amyloid-beta immunoreactivity was detected in the wall of leptomeningeal and parenchymal vessels and in the neuropil, whereas phosphorylated tau, neurofibrillary changes, and neuritic plaques were absent. CONCLUSIONS These findings expand the number of APP mutations linked to hereditary cerebral hemorrhage with amyloidosis, reinforcing the link between this phenotype and codon 693 of APP.

Epidemiology and genetics of frontotemporal dementia: a door-to-door survey in Southern Italy

The objectives of this study were to estimate frontotemporal dementia (FTD) prevalence, identify FTD-related mutations, and correlate FTD phenotype with mutations in a southern Italian population. The study population consisted of subjects ≥ 50 years of age residing in the Community of Biv. on January 1, 2004, and a door-to-door 2-phase design was used. Genetic and biochemical analyses were done on samples collected from 32 patients. Prevalence rates were 0.6 for Alzheimers disease, 0.4 for vascular dementia (VD), 3.5 for FTD, 0.2 for Parkinson dementia, and 1.2 for unspecified dementia. Three GRN (1 known and 2 novel) mutations with reduced plasma protein levels were found associated to 3 distinct phenotypes (behavioral, affective, and delirious type). We report an unusually high FTD prevalence in the investigated population, but a low prevalence of Alzheimers disease. We confirm the heterogeneity of FTD phenotype associated with different GRN mutations.

Acute reversible parkinsonism in a diabetic-uremic patient

Acute movement disorders with basal ganglia lesions have been recently described in diabetic-uremic patients of Asian descent. The process is often reversible, with a favourable clinical outcome. Metabolic (i.e. uremic toxins) and microangiopathic changes have been suggested to be involved in its pathophysiology, even though racial and/or genetic factors might play a role too. In this report, we present a Caucasian diabetic patient with a long-lasting mild uremia in which acute parkinsonism occurred after a steep and unexpected increase of the serum creatinine. The follow-up demonstrated a significant improvement of the neurological signs and symptoms, the creatinine level lowered close to the premorbid levels, and after several months the patient had fully recovered. Our case history suggests that this unusual clinical syndrome is most probably not restricted to Asian patients. Because its potentially favourable outcome, it should be regularly included in the differential diagnosis of acute movement disorders.

NGF controls APP cleavage by downregulating APP phosphorylation at Thr668: relevance for Alzheimer's disease

NGF has been implicated in forebrain neuroprotection from amyloidogenesis and Alzheimers disease (AD). However, the underlying molecular mechanisms are still poorly understood. Here, we investigated the role of NGF signalling in the metabolism of amyloid precursor protein (APP) in forebrain neurons using primary cultures of septal neurons and acute septo‐hippocampal brain slices. In this study, we show that NGF controls the basal level of APP phosphorylation at Thr668 (T668) by downregulating the activity of the Ser/Thr kinase JNK(p54) through the Tyr kinase signalling adaptor SH2‐containing sequence C (ShcC). We also found that the specific NGF receptor, Tyr kinase A (TrkA), which is known to bind to APP, fails to interact with the fraction of APP molecules phosphorylated at T668 (APPpT668). Accordingly, the amount of TrkA bound to APP is significantly reduced in the hippocampus of ShcC KO mice and of patients with AD in which elevated APPpT668 levels are detected. NGF promotes TrkA binding to APP and APP trafficking to the Golgi, where APP–BACE interaction is hindered, finally resulting in reduced generation of sAPPβ, CTFβ and amyloid‐beta (1‐42). These results demonstrate that NGF signalling directly controls basal APP phosphorylation, subcellular localization and BACE cleavage, and pave the way for novel approaches specifically targeting ShcC signalling and/or the APP–TrkA interaction in AD therapy.

Tumor Diagnosis Preceding Alzheimer's Disease Onset: Is There a Link Between Cancer and Alzheimer's Disease?

Studies reporting an inverse association between Alzheimers disease (AD) and cancer are scant. Available data are mostly based on ancillary findings of mortality data or obtained from studies evaluating frequency of neoplasms in AD patients independently if they occurred before or after AD. Moreover, some studies estimated frequencies of neoplasms in demented individuals, who were not necessarily AD patients. We estimated frequency of tumors preceding the onset of AD in AD patients and compared it to that of age- and gender-matched AD-free individuals. Occurrence of tumors preceding AD onset was assessed through a semi-structured questionnaire. Tumors were categorized as benign, malignant, or of uncertain classification and as endocrine-related or not. Odds ratios (OR), used as measure of the association between the two diseases, were adjusted for tumor categories and known risk factors for AD and tumors. We included 126 AD patients and 252 matched controls. Tumor frequency before AD onset was 18.2% among cases and 24.2% among controls. There was a suggestive trend of an overall inverse association between the two diseases (adjusted OR 0.6; 95% CI 0.4-1.1; p = 0.11). Risk for neoplasms was significantly reduced only for women (adjusted OR, 0.5; 95% CI 0.3-0.9; p = 0.03) and for endocrine related tumors (adjusted OR, 0.5; 95% CI 0.2-1; p = 0.04). Our study confirms the inverse association reported in previous epidemiological studies. Though our findings might be explained by processes playing an opposite role in tumors development and neurodegeneration, they are also suggestive for a possible role of estrogen.

Neocortical Variation of Aβ Load in Fully Expressed, Pure Alzheimer's Disease

The relationship between amyloid-beta (Abeta) deposition and tau-related neurofibrillary changes is a key issue in the pathogenesis of Alzheimers disease (AD). The aim of this study was to investigate the extent and cortical distribution of Abeta and tau pathology, their mutual links and their correlation with the duration of the disease in thirty-nine patients with fully expressed AD. By tau immunohistochemistry, we identified different patterns of distribution of neurofibrillary changes that were ascribed to Braak stage V and VI. The disease duration was longer in patients at Braak stage VI than in those at V. Morphometric analysis carried out in several neocortical areas demonstrated that Abeta load was not uniform among individuals and also varied in the same patient throughout the neocortex, showing decreased severity from associative fields in the premotor and primary motor areas. Abeta load was higher at Braak stage VI than at stage V and correlated positively with disease duration in primary motor cortex and in superior temporal gyrus. Overall, we documented a marked heterogeneity in the extent of Abeta deposition even in AD brains at final stages of disease that cannot be completely explained by a simple, regular build up of this pathologic protein in the cerebral cortex during the course of the disease. This study may be relevant for the correct evaluation of therapeutic strategies for AD that specifically address Abeta pathology.

Lipofuscin Hypothesis of Alzheimer’s Disease

The primary culprit responsible for Alzheimer’s disease (AD) remains unknown. Aβ protein has been identified as the main component of amyloid of senile plaques, the hallmark lesion of AD, but it is not definitively established whether the formation of extracellular Aβ deposits is the absolute harbinger of the series of pathological events that hit the brain in the course of sporadic AD. The aim of this paper is to draw attention to a relatively overlooked age-related product, lipofuscin, and advance the hypothesis that its release into the extracellular space following the death of neurons may substantially contribute to the formation of senile plaques. The presence of intraneuronal Aβ, similarities between AD and age-related macular degeneration, and the possible explanation of some of the unknown issues in AD suggest that this hypothesis should not be discarded out of hand.

Haptoglobin interacts with Apolipoprotein e and beta-amyloid and influences their crosstalk

Beta-amyloid accumulation in brain is a driving force for Alzheimers disease pathogenesis. Apolipoprotein E (ApoE) represents a critical player in beta-amyloid homeostasis, but its role in disease progression is controversial. We previously reported that the acute-phase protein haptoglobin binds ApoE and impairs its function in cholesterol homeostasis. The major aims of this study were to characterize the binding of haptoglobin to beta-amyloid, and to evaluate whether haptoglobin affects ApoE binding to beta-amyloid. Haptoglobin is here reported to form a complex with beta-amyloid as shown by immunoblotting experiments with purified proteins, or by its immunoprecipitation in brain tissues from patients with Alzheimers disease. The interaction between ApoE and beta-amyloid was previously shown to be crucial for limiting beta-amyloid neurotoxicity and for promoting its clearance. We demonstrate that haptoglobin, rather than impairing ApoE binding to beta-amyloid, promotes to a different extent the formation of the complex between beta-amyloid and ApoE2 or ApoE3 or ApoE4. Our data suggest that haptoglobin and ApoE functions in brain should be evaluated taking into account their mutual interaction with beta-amyloid. Hence, the risk of developing Alzheimers disease might not only be linked to the different ApoE isoforms, but also rely on the level of critical ligands, such as haptoglobin.

Homozygous carriers of APP A713T mutation in an autosomal dominant Alzheimer disease family

Objective: To report, for the first time, a large autosomal dominant Alzheimer disease (AD) family in which the APP A713T mutation is present in the homozygous and heterozygous state. To date, the mutation has been reported as dominant, and in the heterozygous state associated with familial AD and cerebrovascular lesions. Methods: The family described here has been genealogically reconstructed over 6 generations dating back to the 19th century. Plasma β-amyloid peptide was measured. Sequencing of causative AD genes was performed. Results: Twenty-one individuals, all but 1 born from 2 consanguineous unions, were studied: 8 were described as affected through history, 5 were studied clinically and genetically, and 8 were asymptomatic at-risk subjects. The A713T mutation was detected in the homozygous state in 3 patients and in the heterozygous state in 8 subjects (6 asymptomatic and 2 affected). Conclusions: Our findings, also supported by the β-amyloid plasma assay, confirm (1) the pathogenic role of the APP A713T mutation, (2) the specific phenotype (AD with cerebrovascular lesions) associated with this mutation, and (3) the large span of age at onset, not influenced by APOE, TOMM40, and TREM2 genes. No substantial differences concerning clinical phenotype were evidenced between heterozygous and homozygous patients, in line with the classic definition of dominance. Therefore, in this study, AD followed the classic definition of a dominant disease, contrary to that reported in a previously described AD family with recessive APP mutation. This confirms that genetic AD may be considered a disease with dominant and recessive traits of inheritance.