Entorhinal cortex epigenome-wide association study highlights four novel loci showing differential methylation in Alzheimer's disease.

BACKGROUND: Studies on DNA methylation (DNAm) in Alzheimer's disease (AD) have recently highlighted several genomic loci showing association with disease onset and progression. METHODS: Here, we conducted an epigenome-wide association study (EWAS) using DNAm profiles in entorhinal cortex (EC) from 149 AD patients and control brains and combined these with two previously published EC datasets by meta-analysis (total n = 337). RESULTS: We identified 12 cytosine-phosphate-guanine (CpG) sites showing epigenome-wide significant association with either case-control status or Braak's tau-staging. Four of these CpGs, located in proximity to CNFN/LIPE, TENT5A, PALD1/PRF1, and DIRAS1, represent novel findings. Integrating DNAm levels with RNA sequencing-based mRNA expression data generated in the same individuals showed significant DNAm-mRNA correlations for 6 of the 12 significant CpGs. Lastly, by calculating rates of epigenetic age acceleration using two recently proposed "epigenetic clock" estimators we found a significant association with accelerated epigenetic aging in the brains of AD patients vs. controls. CONCLUSION: In summary, our study represents the hitherto most comprehensive EWAS in AD using EC and highlights several novel differentially methylated loci with potential effects on gene expression.

Cerebrospinal fluid proteomic profiling of individuals with mild cognitive impairment and suspected non-Alzheimer's disease pathophysiology.

BACKGROUND: Suspected non-Alzheimer's disease pathophysiology (SNAP) is a biomarker concept that encompasses individuals with neuronal injury but without amyloidosis. We aim to investigate the pathophysiology of SNAP, defined as abnormal tau without amyloidosis, in individuals with mild cognitive impairment (MCI) by cerebrospinal fluid (CSF) proteomics. METHODS: Individuals were classified based on CSF amyloid beta (Aß)1-42 (A) and phosphorylated tau (T), as cognitively normal A-T- (CN), MCI A-T+ (MCI-SNAP), and MCI A+T+ (MCI-AD). Proteomics analyses, Gene Ontology (GO), brain cell expression, and gene expression analyses in brain regions of interest were performed. RESULTS: A total of 96 proteins were decreased in MCI-SNAP compared to CN and MCI-AD. These proteins were enriched for extracellular matrix (ECM), hemostasis, immune system, protein processing/degradation, lipids, and synapse. Fifty-one percent were enriched for expression in the choroid plexus. CONCLUSION: The pathophysiology of MCI-SNAP (A-T+) is distinct from that of MCI-AD. Our findings highlight the need for a different treatment in MCI-SNAP compared to MCI-AD.

Genotype-Phenotype Relations in Primary Familial Brain Calcification: Systematic MDSGene Review.

This systematic MDSGene review covers individuals with confirmed genetic forms of primary familial brain calcification (PFBC) available in the literature. Data on 516 (47% men) individuals, carrying heterozygous variants in SLC20A2 (solute carrier family 20 member 2, 61%), PDGFB (platelet-derived growth factor subunit B, 12%), XPR1 (xenotropic and polytropic retrovirus receptor, 16%), or PDGFRB (platelet-derived growth factor receptor beta, 5%) or biallelic variants in MYORG (myogenesis-regulating glycosidase, 13%) or JAM2 (junctional adhesion molecule 2, 2%), were extracted from 93 articles. Nearly one-third of the mutation carriers were clinically unaffected. Carriers of PDGFRB variants were more likely to be clinically unaffected (~54%), and the penetrance of SLC20A2 and XPR1 variants (<70%) was lower in comparison to the remaining three genes (>85%). Among the 349 clinically affected patients, 27% showed only motor and 31% only nonmotor symptoms/signs, whereas the remaining 42% had a combination thereof. While parkinsonism and speech disturbance were the most frequently reported motor manifestations, cognitive deficits, headache, and depression were the major nonmotor symptoms/signs. The basal ganglia were always calcified, and the cerebellum, thalamus, and white matter contained calcifications in 58%, 53%, and 43%, respectively, of individuals. In autosomal-dominant PFBC, mutation severity influenced the number of calcified brain areas, which in turn correlated with the clinical status, whereby the risk of developing symptoms/signs more than doubled for each additional region with calcifications. Our systematic analysis provides the most comprehensive insight into genetic, clinical, and neuroimaging features of known PFBC forms, to date. In addition, it puts forth the penetrance estimates and newly discovered genotype-phenotype relations that will improve counseling of individuals with mutations in PFBC genes. © 2021 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

PHACTR1 genetic variability is not critical in small vessel ischemic disease patients and PcomA recruitment in C57BL/6J mice.

Recently, several genome-wide association studies identified PHACTR1 as key locus for five diverse vascular disorders: coronary artery disease, migraine, fibromuscular dysplasia, cervical artery dissection and hypertension. Although these represent significant risk factors or comorbidities for ischemic stroke, PHACTR1 role in brain small vessel ischemic disease and ischemic stroke most important survival mechanism, such as the recruitment of brain collateral arteries like posterior communicating arteries (PcomAs), remains unknown. Therefore, we applied exome and genome sequencing in a multi-ethnic cohort of 180 early-onset independent familial and apparently sporadic brain small vessel ischemic disease and CADASIL-like Caucasian patients from US, Portugal, Finland, Serbia and Turkey and in 2 C57BL/6J stroke mouse models (bilateral common carotid artery stenosis [BCCAS] and middle cerebral artery occlusion [MCAO]), characterized by different degrees of PcomAs patency. We report 3 very rare coding variants in the small vessel ischemic disease-CADASIL-like cohort (p.Glu198Gln, p.Arg204Gly, p.Val251Leu) and a stop-gain mutation (p.Gln273*) in one MCAO mouse. These coding variants do not cluster in PHACTR1 known pathogenic domains and are not likely to play a critical role in small vessel ischemic disease or brain collateral circulation. We also exclude the possibility that copy number variants (CNVs) or a variant enrichment in Phactr1 may be associated with PcomA recruitment in BCCAS mice or linked to diverse vascular traits (cerebral blood flow pre-surgery, PcomA size, leptomeningeal microcollateral length and junction density during brain hypoperfusion) in C57BL/6J mice, respectively. Genetic variability in PHACTR1 is not likely to be a common susceptibility factor influencing small vessel ischemic disease in patients and PcomA recruitment in C57BL/6J mice. Nonetheless, rare variants in PHACTR1 RPEL domains may influence the stroke outcome and are worth investigating in a larger cohort of small vessel ischemic disease patients, different ischemic stroke subtypes and with functional studies.

Primary fatty amides in plasma associated with brain amyloid burden, hippocampal volume, and memory in the European Medical Information Framework for Alzheimer's Disease biomarker discovery cohort.

INTRODUCTION: A critical and as-yet unmet need in Alzheimer's disease (AD) is the discovery of peripheral small molecule biomarkers. Given that brain pathology precedes clinical symptom onset, we set out to test whether metabolites in blood associated with pathology as indexed by cerebrospinal fluid (CSF) AD biomarkers. METHODS: This study analyzed 593 plasma samples selected from the European Medical Information Framework for Alzheimer's Disease Multimodal Biomarker Discovery study, of individuals who were cognitively healthy (n = 242), had mild cognitive impairment (n = 236), or had AD-type dementia (n = 115). Logistic regressions were carried out between plasma metabolites (n = 883) and CSF markers, magnetic resonance imaging, cognition, and clinical diagnosis. RESULTS: Eight metabolites were associated with amyloid ß and one with t-tau in CSF, these were primary fatty acid amides (PFAMs), lipokines, and amino acids. From these, PFAMs, glutamate, and aspartate also associated with hippocampal volume and memory. DISCUSSION: PFAMs have been found increased and associated with amyloid ß burden in CSF and clinical measures.

Mutations in the gene encoding PDGF-B cause brain calcifications in humans and mice.

Calcifications in the basal ganglia are a common incidental finding and are sometimes inherited as an autosomal dominant trait (idiopathic basal ganglia calcification (IBGC)). Recently, mutations in the PDGFRB gene coding for the platelet-derived growth factor receptor ß (PDGF-Rß) were linked to IBGC. Here we identify six families of different ancestry with nonsense and missense mutations in the gene encoding PDGF-B, the main ligand for PDGF-Rß. We also show that mice carrying hypomorphic Pdgfb alleles develop brain calcifications that show age-related expansion. The occurrence of these calcium depositions depends on the loss of endothelial PDGF-B and correlates with the degree of pericyte and blood-brain barrier deficiency. Thus, our data present a clear link between Pdgfb mutations and brain calcifications in mice, as well as between PDGFB mutations and IBGC in humans.

Mutational analysis of ATP7B gene and the genotype-phenotype correlation in patients with Wilson's disease in Serbia.

BACKGROUND/AIM: Wilson's disease (WD) is an autosomal-recessive disorder which is characterized with a marked clinical heterogeneity. The gene responsible for WD is located in 13q14.3 chromosome, contains 21 exons and codes for copper specific transporting P-type adenosinetriphosphatase (ATPase) (ATP7B). Mutations in ATP7B gene change biosynthetic and transporting role of ATPase in cell leading to damaged billiary excretion of copper and its accumulation in the liver, brain, cornea and other tissues. Until now, it has been described more than 400 mutations in ATP7B gene with characteristic geographic distribution. The aim of this study was to assess the spectrum of mutations of ATP7B gene on a large number of patients in Serbian population and to make a correlation between particular genotypes and specific phenotypes. METHODS: Eighty-six consecutive patients with WD from WD Clinical Research programme were included in this study. Genetic analysis was performed by direct gene sequencing method. RESULTS: Mutations in ATP7B gene were found in 93% analyzed patients (81.4% of all alleles analyzed). Thirteen mutations were identified, one of which (G998E) was the novel one, so far undescribed in the literature. The most frequent mutation in our population was H1069Q, which was present in 38.4% patients, and the second most frequent mutation was 2304-2305insC (11.6%). Also, a great number of gene polymorphisms of DNA sequences, which do not disturb the ATP7B gene function, was identified. Although neurological form of the disease was more frequent in the group of homozygous for H1069Q and the group of non-H1069Q carriers, there was no statistically significant difference between the groups. CONCLUSION: Our research showed that genetic diagnosis of WD can be done in 80% of cases by analysis of 5 most common mutations in our population, which facilitate diagnosis significantly. There was no correlation between different genotypes and specific phenotypic features of WD, the presence of psychiatric disturbances and cognitive deterioration.

Mutations in SLC20A2 are a major cause of familial idiopathic basal ganglia calcification.

Familial idiopathic basal ganglia calcification (IBGC) or Fahr's disease is a rare neurodegenerative disorder characterized by calcium deposits in the basal ganglia and other brain regions, which is associated with neuropsychiatric and motor symptoms. Familial IBGC is genetically heterogeneous and typically transmitted in an autosomal dominant fashion. We performed a mutational analysis of SLC20A2, the first gene found to cause IBGC, to assess its genetic contribution to familial IBGC. We recruited 218 subjects from 29 IBGC-affected families of varied ancestry and collected medical history, neurological exam, and head CT scans to characterize each patient's disease status. We screened our patient cohort for mutations in SLC20A2. Twelve novel (nonsense, deletions, missense, and splice site) potentially pathogenic variants, one synonymous variant, and one previously reported mutation were identified in 13 families. Variants predicted to be deleterious cosegregated with disease in five families. Three families showed nonsegregation with clinical disease of such variants, but retrospective review of clinical and neuroimaging data strongly suggested previous misclassification. Overall, mutations in SLC20A2 account for as many as 41% of our familial IBGC cases. Our screen in a large series expands the catalog of SLC20A2 mutations identified to date and demonstrates that mutations in SLC20A2 are a major cause of familial IBGC. Non-perfect segregation patterns of predicted deleterious variants highlight the challenges of phenotypic assessment in this condition with highly variable clinical presentation.

Could spindle cell lung carcinoma be considered and treated as sarcoma, according to its clinical course, morphology, immunophenotype and genetic finding?

The actual nature of spindle cell carcinoma has been debated extensively because of its rarity. It carries a poor prognosis, even when early-stage disease is diagnosed and resected. In view of the rarity and the significance of the histological diagnosis, we report a patient with rapidly progressing spindle cell lung carcinoma with soft tissue metastasis. Diagnosis was confirmed by immunohistochemistry finding. Analysis of the TP53 gene mutations by polymerase chain reaction and DNA sequencing revealed insertion of single thymine resulting in frameshift mutation in the exon 8. Prognosis of spindle cell lung carcinoma might be determined by the sarcoma component of the tumor and, based on that, we wonder if this type of lung carcinoma could be followed-up and treated by strategies for soft tissue sarcomas, because of its rapid, sarcomatous type of growth, beside the properly lung carcinoma oncological treatment.

Exclusion of linkage to chromosomes 14q, 2q37 and 8p21.1-q11.23 in a Serbian family with idiopathic basal ganglia calcification.

In this study we report clinical and imaging data from a multigenerational Serbian family with idiopathic basal ganglia calcification (IBGC) and exclusion of linkage to chromosome 14q, 2q37 and 8p21.1-q11.23. Fourteen out of 18 family members were personally examined and 11 of them were scanned with computed tomography (CT). CT scans revealed existence of symmetrical calcifications in six family members from three generations (four symptomatic and two asymptomatic). Age at onset of clinical symptoms varied between 22.0 and 55.4 years. The main clinical findings included parkinsonism, severe gait disturbances with freezing of gait, and dyskinesia. Hyperechogenicities identified by transcranial sonography corresponded well to the CT images of hyperintense calcifications in the same structures, whereas brain perfusion single photon emission computed tomography demonstrated predominant hypoperfusion in the frontal cortex and the basal ganglia. After exclusion of linkage to known loci, our pedigree with IBGC further demonstrates locus heterogeneity in this disorder. Analysis of clinically affected individuals supports observation that the clinical features of IBGC appear to be varied both within and between families. The age at onset of the clinical symptoms appeared to be decreasing in two observed transmissions, suggestive of possible genetic anticipation.