Genetic Architecture and Molecular, Imaging and Prodromic Markers in Dementia with Lewy Bodies: State of the Art, Opportunities and Challenges

Dementia with Lewy bodies (DLB) is one of the most common causes of dementia and belongs to the group of α-synucleinopathies. Due to its clinical overlap with other neurodegenerative disorders and its high clinical heterogeneity, the clinical differential diagnosis of DLB from other similar disorders is often difficult and it is frequently underdiagnosed. Moreover, its genetic etiology has been studied only recently due to the unavailability of large cohorts with a certain diagnosis and shows genetic heterogeneity with a rare contribution of pathogenic mutations and relatively common risk factors. The rapid increase in the reported cases of DLB highlights the need for an easy, efficient and accurate diagnosis of the disease in its initial stages in order to halt or delay the progression. The currently used diagnostic methods proposed by the International DLB consortium rely on a list of criteria that comprises both clinical observations and the use of biomarkers. Herein, we summarize the up-to-now reported knowledge on the genetic architecture of DLB and discuss the use of prodromal biomarkers as well as recent promising candidates from alternative body fluids and new imaging techniques

Patient-Derived Induced Pluripotent Stem Cells (iPSCs) and Cerebral Organoids for Drug Screening and Development in Autism Spectrum Disorder: Opportunities and Challenges

Autism spectrum disorder (ASD) represents a group of neurodevelopmental diseases characterized by persistent deficits in social communication, interaction, and repetitive patterns of behaviors, interests, and activities. The etiopathogenesis is multifactorial with complex interactions between genetic and environmental factors. The clinical heterogeneity and complex etiology of this pediatric disorder have limited the development of pharmacological therapies. The major limit to ASD research remains a lack of relevant human disease models which can faithfully recapitulate key features of the human pathology and represent its genetic heterogeneity. Recent advances in induced pluripotent stem cells (iPSCs), reprogrammed from somatic cells of patients into all types of patient-specific neural cells, have provided a promising cellular tool for disease modeling and development of novel drug treatments. The iPSCs technology allowed not only a better investigation of the disease etiopathogenesis but also opened up the potential for personalized therapies and offered new opportunities for drug discovery, pharmacological screening, and toxicity assessment. Moreover, iPSCs can be differentiated and organized into three-dimensional (3D) organoids, providing a model which mimics the complexity of the brain’s architecture and more accurately recapitulates tissue- and organ-level disease pathophysiology. The aims of this review were to describe the current state of the art of the use of human patient-derived iPSCs and brain organoids in modeling ASD and developing novel therapeutic strategies and to discuss the opportunities and major challenges in this rapidly moving field

Molecular and Imaging Biomarkers in Alzheimer’s Disease: A Focus on Recent Insights

Alzheimer’s disease (AD) is the most common neurodegenerative disease among the elderly, affecting millions of people worldwide and clinically characterized by a progressive and irreversible cognitive decline. The rapid increase in the incidence of AD highlights the need for an easy, efficient and accurate diagnosis of the disease in its initial stages in order to halt or delay the progression. The currently used diagnostic methods rely on measures of amyloid-β (Aβ), phosphorylated (p-tau) and total tau (t-tau) protein levels in the cerebrospinal fluid (CSF) aided by advanced neuroimaging techniques like positron emission tomography (PET) and magnetic resonance imaging (MRI). However, the invasiveness of these procedures and the high cost restrict their utilization. Hence, biomarkers from biological fluids obtained using non-invasive methods and novel neuroimaging approaches provide an attractive alternative for the early diagnosis of AD. Such biomarkers may also be helpful for better understanding of the molecular mechanisms underlying the disease, allowing differential diagnosis or at least prolonging the pre-symptomatic stage in patients suffering from AD. Herein, we discuss the advantages and limits of the conventional biomarkers as well as recent promising candidates from alternative body fluids and new imaging techniques

Can SARS-CoV-2 Infection Exacerbate Alzheimer’s Disease? An Overview of Shared Risk Factors and Pathogenetic Mechanisms

The current coronavirus disease 2019 (COVID-19) pandemic, caused by severe acute respiratory syndrome coronavirus (SARS-CoV)-2, is affecting every aspect of global society, including public healthcare systems, medical care access, and the economy. Although the respiratory tract is primarily affected by SARS-CoV-2, emerging evidence suggests that the virus may also reach the central nervous system (CNS), leading to several neurological issues. In particular, people with a diagnosis of Alzheimer’s disease (AD) are a vulnerable group at high risk of contracting COVID-19, and develop more severe forms and worse outcomes, including death. Therefore, understanding shared links between COVID-19 and AD could aid the development of therapeutic strategies against both. Herein, we reviewed common risk factors and potential pathogenetic mechanisms that might contribute to the acceleration of neurodegenerative processes in AD patients infected by SARS-CoV-2

Evidence for a fourth locus for autosomal dominant nocturnal frontal lobe epilepsy

Mutations responsible for autosomal dominant nocturnal frontal lobe epilepsy have been identified in two members of the neuronal nicotinic acetylcholine receptor gene family: CHRNA4(ENFL1 locus) and CHRNB2 (ENFL3 locus) coding for alpha4 and beta2 subunit, respectively. However, mutations in these genes account for only a minority (less than 10%) of cases. For a third ADNFLE locus (ENFL2) on chromosome 15q24 the gene was not identified. The involvement of the three loci in the pathogenesis of ADNFLE was investigated in 12 unrelated Italian families, selected on the basis of anamnestic and video-polysomnographic data. Compliant family members were typed for polymorphic markers spanning the analyzed chromosome regions. Linkage analyses excluded association of all chromosome regions with ADNFLE in 72% of cases. In two, four and one families it was impossible to ascertain or exclude association with ENFL1, ENFL2, or ENFL3, respectively, however, no mutations have been detected in the nicotinic receptor genes located in these regions. These data strongly suggest that ENFL1, ENFL2 and ENFL3 are minor loci for the disease and point to the existence of at least a fourth locus for ADNFLE

Exome Sequencing in an ADSHE Family: VUS Identification and Limits

Autosomal dominant sleep-related hypermotor epilepsy (ADSHE) is the familial form of a focal epilepsy characterized by hyperkinetic focal seizures, mainly arising during non-rapid eye movements (NREM) sleep. Mutations associated with ADSHE account for a small proportion of the genetically determined cases, suggesting the existence of other disease-causing genes. Here, we reported the results obtained by performing trio-based whole-exome sequencing (WES) in an Italian family showing ADSHE and investigated the structural impact of putative variants by in silico modeling analysis. We identified a p.(Trp276Gly) variant in MOXD1 gene encoding the monooxigenase DBH like 1 protein, cosegregating with the disease and annotated as VUS under the ACMG recommendations. Structural bioinformatic analysis predicted a high destabilizing effect of this variant, due to the loss of important hydrophilic bonds and an expansion of cavity volume in the protein hydrophobic core. Although our data support a functional effect of the p.(Trp276Gly) variant, we highlight the need to identify additional families carrying MOXD1 mutations or functional analyses in suitable models to clarify its role in ADSHE pathogenesis. Moreover, we discuss the importance of VUS reporting due to the low rate of pathogenic variant identification by NGS in epilepsy and for future reinterpretation studies

A Novel KCNJ2 Mutation Identified in an Autistic Proband Affects the Single Channel Properties of Kir2.1

Inwardly rectifying potassium channels (Kir) have been historically associated to several cardiovascular disorders. In particular, loss-of-function mutations in the Kir2.1 channel have been reported in cases affected by Andersen-Tawil syndrome while gain-of-function mutations in the same channel cause the short QT3 syndrome. Recently, a missense mutation in Kir2.1, as well as mutations in the Kir4.1, were reported to be involved in autism spectrum disorders (ASDs) suggesting a role of potassium channels in these diseases and introducing the idea of the existence of K+ channel ASDs. Here, we report the identification in an Italian affected family of a novel missense mutation (p.Phe58Ser) in the KCNJ2 gene detected in heterozygosity in a proband affected by autism and borderline for short QT syndrome type 3. The mutation is located in the N-terminal region of the gene coding for the Kir2.1 channel and in particular in a very conserved domain. In vitro assays demonstrated that this mutation results in an increase of the channel conductance and in its open probability. This gain-of-function of the protein is consistent with the autistic phenotype, which is normally associated to an altered neuronal excitability

A rescuable folding defective Na v 1.1 ( SCN1A ) sodium channel mutant causes GEFS+: Common mechanism in Na v 1.1 related epilepsies?

International audienc

Analysis of Human Papillomavirus (HPV) 16 Variants Associated with Cervical Infection in Italian Women

This study aims to evaluate HPV16 variants distribution in a population of Italian women living in two different regions (Lombardy and Sardinia) by sequence analyses of HPV16-positive cervical samples, in order to reconstruct the phylogenetic relationship among variants to identify the currently circulating lineages. Analyses were conducted starting from DNA isolated from 67 HPV16-positive cervical samples collected from two different Italian centres (31 from Lombardy and 36 from Sardinia) of women with normal and abnormal cervical cytology. The entire long control region (LCR) and 300 nt of the E6 gene was sequenced to identify intra-type variants. Sequence comparison and phylogenetic analysis were made using a distance-based neighbour joining method (NJ) and Kimura two-parameter model. Data obtained reported that Italian sequences mainly belonged to the European lineage, in particular sublineage A2. Only five sequences clustered in non-European branches: two in North American lineage (sublineage D1), two in African-1 (sublineage B1) and one in African-2. A new 27 nucleotide duplication in the central segment of the LCR region was found in a sequence obtained from a sample isolated in Sardinia. A predominance of European variants was detected, with some degree of variability among the studied HPV16 strains. This study contributes to the implementation of data regarding the molecular epidemiology of HPV16 variants