V roce 2009 se metoda masivního paralelního sekvenování (NGS) prokázala jako velmi účinný nástroj při identifikaci variant, které souvisí s mnoha neurodegenerativními nemocemi. Množství genetických dat mělo významný dopad na klinickou diagnózu a zároveň významně přispělo k objevu molekulárních mechanismů, které jsou základem těchto onemocnění. Nicméně objasnění rolí nalezených variant identifikovaných NGS, a zejména variant nejasného významu (VUS), je náročné a je zcela klíčová spolupráce genetika, neurologa a neuropatologa. Vytvoření konsenzuálních postupů a vývoj veřejných genomických/fenotypových databází jsou proto zásadní pro usnadnění sdílení a ověřování údajů. Práce poskytuje systematický přehled nejčastějších mutací u neuropatologicky diagnostikovaných pacientů s neurodegenerativním onemocněním a shrnuje techniky genetické diagnostiky a význam bioinformatiky při interpretaci výsledků neurodegenerativních onemocnění na příkladu 5 zajímavých kazuistik.
In 2009, next-generation sequencing (NGS) proved to be a very powerful tool in identifying variants associated with many neurodegenerative diseases. Whole-exome sequencing and whole-genome sequencing are effective for identifying variants in new or unexpected genes responsible for inherited diseases, while targeted sequencing is useful in detecting variants in previously known disease-associated genes. The wealth of genetic data provided by NGS has had a significant impact on clinical diagnoses while contributing to these discoveries of the molecular mechanisms underlying disease. However, eluciding the roles of the found variants identified by NGS, and especially the variants of unclear significance (VUS), is challenging and the cooperation of a geneticist, a neurologist and a neuropathologist is absolutely key. The establishment of consensus guidelines and the development of public genomic/phenotypic databases are therefore essential to facilitate data sharing and validation. In this review article, we will provide a systematic overview of the most frequent mutations in neuropathologically diagnosed patients with neurodegenerative diseases and summarize genetic diagnostic techniques and the importance of bioinformatics in the interpretation of neurodegenerative disease results.
- MeSH
- Alzheimerova nemoc diagnóza genetika patologie MeSH
- amyotrofická laterální skleróza diagnóza genetika patologie MeSH
- Creutzfeldtova-Jakobova nemoc diagnóza genetika patologie MeSH
- diagnostické techniky molekulární MeSH
- frontotemporální lobární degenerace diagnóza genetika patologie MeSH
- genetická predispozice k nemoci genetika MeSH
- genetické testování metody MeSH
- Gerstmannova-Strausslerova-Scheinkerova nemoc diagnóza genetika patologie MeSH
- lidé MeSH
- neurodegenerativní nemoci * diagnóza genetika patologie MeSH
- vysoce účinné nukleotidové sekvenování metody MeSH
- Check Tag
- lidé MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- Publikační typ
- kazuistiky MeSH
Creutzfeldt-Jakob disease (CJD), the most common human prion disorder, may occur as "pure" neurodegeneration with isolated prion deposits in the brain tissue; however, comorbid cases with different concomitant neurodegenerative diseases have been reported. This retrospective study examined correlations of clinical, neuropathological, molecular-genetic, immunological, and neuroimaging biomarkers in pure and comorbid CJD. A total of 215 patients have been diagnosed with CJD during the last ten years by the Czech National Center for Prion Disorder Surveillance. Data were collected from all patients with respect to diagnostic criteria for probable CJD, including clinical description, EEG, MRI, and CSF findings. A detailed neuropathological analysis uncovered that only 11.16% were "pure" CJD, while 62.79% had comorbid tauopathy, 20.47% had Alzheimer's disease, 3.26% had frontotemporal lobar degeneration, and 2.33% had synucleinopathy. The comorbid subgroup analysis revealed that tauopathy was linked to putaminal hyperintensity on MRIs, and AD mainly impacted the age of onset, hippocampal atrophy on MRIs, and beta-amyloid levels in the CSF. The retrospective data analysis found a surprisingly high proportion of comorbid neuropathologies; only 11% of cases were verified as "pure" CJD, i.e., lacking hallmarks of other neurodegenerations. Comorbid neuropathologies can impact disease manifestation and can complicate the clinical diagnosis of CJD.
- Publikační typ
- časopisecké články MeSH
Human prion disorders (transmissible spongiform encephalopathies, TSEs) are unique, progressive, and fatal neurodegenerative diseases caused by aggregation of misfolded prion protein in neuronal tissue. Due to the potential transmission, human TSEs are under active surveillance in a majority of countries; in the Czech Republic data are centralized at the National surveillance center (NRL) which has a clinical and a neuropathological subdivision. The aim of our article is to review current knowledge about human TSEs and summarize the experience of active surveillance of human prion diseases in the Czech Republic during the last 20 years. Possible or probable TSEs undergo a mandatory autopsy using a standardized protocol. From 2001 to 2020, 305 cases of sporadic and genetic TSEs including 8 rare cases of Gerstmann-Sträussler-Scheinker syndrome (GSS) were confirmed. Additionally, in the Czech Republic, brain samples from all corneal donors have been tested by the NRL immunology laboratory to increase the safety of corneal transplants since January 2007. All tested 6590 corneal donor brain tissue samples were negative for prion protein deposits. Moreover, the routine use of diagnostic criteria including biomarkers are robust enough, and not even the COVID-19 pandemic has negatively impacted TSEs surveillance in the Czech Republic.
- Publikační typ
- časopisecké články MeSH
- přehledy MeSH
Amyotrophic lateral sclerosis (ALS) is a devastating, uniformly lethal progressive degenerative disorder of motor neurons that overlaps with frontotemporal lobar degeneration (FTLD) clinically, morphologically, and genetically. Although many distinct mutations in various genes are known to cause amyotrophic lateral sclerosis, it remains poorly understood how they selectively impact motor neuron biology and whether they converge on common pathways to cause neuronal degeneration. Many of the gene mutations are in proteins that share similar functions. They can be grouped into those associated with cell axon dynamics and those associated with cellular phagocytic machinery, namely protein aggregation and metabolism, apoptosis, and intracellular nucleic acid transport. Analysis of pathways implicated by mutant ALS genes has provided new insights into the pathogenesis of both familial forms of ALS (fALS) and sporadic forms (sALS), although, regrettably, this has not yet yielded definitive treatments. Many genes play an important role, with TARDBP, SQSTM1, VCP, FUS, TBK1, CHCHD10, and most importantly, C9orf72 being critical genetic players in these neurological disorders. In this mini-review, we will focus on the molecular mechanisms of these two diseases.
- Publikační typ
- časopisecké články MeSH
- přehledy MeSH
Interactions between prion protein (PrP) and tau protein have long been discussed, especially in relation to the pathogenesis of neurodegenerative diseases. The presence of tauopathy in the genetic forms of Creutzfeldt-Jakob disease (CJD) brains is not uncommon. Molecular interactions between PrP and tau protein have been demonstrated in animal models; the role is attributed to the structural properties of misfolded isoform of the host-encoded prion protein (PrPSc) aggregates, especially amyloid, which contributes to the phosphorylation of tau protein, which is reflected in the frequent occurrence of tau pathology in inherited prion amyloidoses. The question is the relationship between PrPSc and hippocampal tau pathology without amyloid deposits (i.e. PART and ARTAG) in sporadic CJD (sCJD). The co-occurrence of these two proteinopathies in sCJD brains is quite rare. These pathological entities have been described in only a few cases of sCJD, all of them were older than 70 years. There have been speculations about the possibility of accelerating the course of pre-existing tauopathy or the possibility of accelerating the ageing process in the CJD brains. Here we present the clinical course and neuropathological findings of a patient with sCJD in whom the above mentioned tauopathies PART and ARTAG, considered to be typical for older age, were found as early as 58 years of age. According to the available information, this case represents an unusually early occurrence of age-related tauopathies not only in relation to sCJD, but also in general.
- MeSH
- Creutzfeldtova-Jakobova nemoc * genetika MeSH
- lidé MeSH
- mozek metabolismus MeSH
- prionová bílkovina genetika MeSH
- priony * genetika metabolismus MeSH
- senioři MeSH
- tauopatie * MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- senioři MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Background: Sporadic Creutzfeldt-Jakob disease (sCJD) is the most common type of a group of transmissible spongiform encephalopathies (prion diseases). The etiology of the sporadic form of CJD is still unclear. sCJD can occur in combination with other neurodegenerative diseases, which further complicates the diagnosis. Alzheimer's disease (AD), e.g., is often seen in conjunction with sCJD. Method: In this study, we performed a systematic analysis of 15 genes related to the most important neurodegenerative diseases - AD, frontotemporal dementia, amyotrophic lateral sclerosis, prion disease, and Parkinson's disease - in a cohort of sCJD and sCJD in comorbidity with AD and primary age-related proteinopathy (PART). A total of 30 neuropathologically verified cases of sCJD with and without additional proteinopathies were included in the study. In addition, we compared microtubule-associated protein tau (MAPT) haplotypes between sCJD patients and patients with sCJD and PART or sCJD and AD. Then we studied the interaction between the Apolipoprotein E gene (APOE) and PRNP in sCJD patients. Results: We did not find any causal mutations in the neurodegenerative disease genes. We did detect a p.E318G missense variant of uncertain significance (VUS) in PSEN1 in three patients. In PRNP, we also found a previously described non-pathogenic insertion (p.P84_Q91Q). Conclusion: Our pilot study failed to find any critical differences between pure sCJD and sCJD in conjunction with other comorbid neurodegenerative diseases. Further investigations are needed to better understand this phenomenon.
- Publikační typ
- časopisecké články MeSH
- MeSH
- Alzheimerova nemoc * genetika MeSH
- genetické testování MeSH
- lidé MeSH
- neurodegenerativní nemoci * genetika MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- přehledy MeSH
Gerstmann-Sträussler-Scheinker syndrome (GSS) with the P102L mutation is a rare genetic prion disease caused by a pathogenic mutation at codon 102 in the prion protein gene. Cluster analysis encompassing data from 7 Czech patients and 87 published cases suggests the existence of 4 clinical phenotypes (typical GSS, GSS with areflexia and paresthesia, pure dementia GSS, and Creutzfeldt-Jakob disease-like GSS); GSS may be more common than previously estimated. In making a clinical diagnosis or progression estimates of GSS, magnetic resonance imaging and real-time quaking-induced conversion may be helpful, but the results should be evaluated with respect to the overall clinical context. ANN NEUROL 2019;86:643-652.
- MeSH
- dospělí MeSH
- fenotyp MeSH
- Gerstmannova-Strausslerova-Scheinkerova nemoc patologie patofyziologie MeSH
- lidé středního věku MeSH
- lidé MeSH
- senioři MeSH
- Check Tag
- dospělí MeSH
- lidé středního věku MeSH
- lidé MeSH
- mužské pohlaví MeSH
- senioři MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Během posledních tří desetiletí byl zaznamenán významný pokrok v chápání molekulární etiologie dědičných neurodegenerativních demencí. Byly objeveny geny pro dědičné neurodegenerativní nemoci a množství studií pro vývoj terapií modifikujících onemocnění narůstá. Většina neurodegenerativních demencí se klinicky liší, ač mají společný patofyziologický dopad. U neurodegenerací dochází k zániku neuronů apoptotickou signální dráhou na podkladě ukládání depozit patologicky změněného proteinu v mozkové tkáni, tzv. proteinopatie. U genetických (dědičných) neurodegenerací hrají zásadní roli v patofyziologických mechanizmech konformační změny proteinů, genové aberace či polymorfizmy. Klinické projevy a neuropatologické nálezy dědičných forem neurodegenerativních demencí jsou často nerozlišitelné od sporadických typů, což zvyšuje potřebu molekulárně genetické analýzy genů zodpovědných za různé neurodegenerace. Účelem sdělení je provést stručný přehled genů, které jsou důležité v patofyziologii neurodegenerativních demencí v rutinní diagnostické praxi a možnosti jejich vyšetření.
Over the past three decades, significant advances have been made in understanding the molecular etiology of hereditary neurodegenerative dementias. Specific genes responsible for hereditary neurodegenerative diseases have been discovered, and studies on the development of disease-modifying therapies have been accelerated. Most neurodegenerative dementias are clinically different, although they share a common pathophysiological background. In neurodegeneration, neuronal atrophy due to apoptotic signalling pathway influenced by deposition of pathologically altered protein in the brain tissue are the leading mechanisms, thus, these diseases are called proteinopathies. In genetic (hereditary) neurodegenerations, conformational changes of proteins, gene aberrations or polymorphisms play crucial roles in pathophysiological mechanisms. Clinical manifestations and neuropathological findings of hereditary forms of neurodegenerative dementia are often inseparable from sporadic types, which increases an urgent need for molecular-genetic analysis of genes responsible for various neurodegenerations. The purpose of this work is to provide a brief overview of the most important genes related to the pathophysiology of neurodegenerative dementias in routine diagnostic practice and the possibilities of their detection.
Úvod: Mutační analýza genu pro receptor epidermálního růstového faktoru (epidermal growth factor receptor - EGFR) z nádorové tkáně je v současnosti standardním testem u pacientů s nemalobuněčným karcinomem plic. Molekulární testování cirkulující nádorové DNA (circulating tumor DNA - ctDNA) z plazmy se ukazuje být spolehlivou alternativou detekce mutací v případech, kdy není možné získat bioptický či cytologický vzorek z nádoru či je třeba monitorovat léčebnou odpověď pomocí opakovaných vyšetření. Navíc dle recentních prací ctDNA lépe odráží heterogenitu nádorového procesu než odběr z izolované nádorové léze či metastázy. Za účelem zhodnocení analytické kvality testování mutací v genu EGFR z ctDNA izolované z plazmy bylo zorganizováno mezilaboratorní porovnání v rámci referenčních laboratoří prediktivní diagnostiky v České republice. Materiál a metody: Celkem 7 laboratořím bylo zasláno 13 komerčně dostupných referenčních vzorků 2 ml plazmy obsahující nejčastější senzitivní mutace genu EGFR (delece v exonu 19, L858R) a rezistentní mutaci T790M s frekvencí mutací 5; 0,5 a 0,05 %. Jeden vyšetřovaný vzorek obsahoval nemutovanou DNA. Vzorky byly analyzovány metodami standardně využívanými v diagnostické praxi. V 6 ze 7 laboratoří byl použit cobas® EGFR Mutation Test v2, v 1 laboratoři Super-ARMS® EGFR Mutation Detection Kit. Výsledky: Určeno bylo 91 genotypů s celkovou chybovostí 24,2 % (22/91). Na 0,5% a vyšší úrovni mutační frekvence činila celková chybovost 3,2 % (2/63), na 5% úrovni 0 % (0/35). Nebyly detekovány žádné falešně pozitivní výsledky. Platforma cobas® dosáhla konzistentně úspěšné detekce na hladině 0,05 % pro deleci v exonu 19. Pro mutace L858R a T790M byl práh detekce nad hodnotou 0,5 %. Závěr: Naše výsledky poukazují na limitovanou citlivost vyšetření mutací EGFR z plazmy, a to zejména mutace T790M. Obzvláště pro vyšetřování ctDNA z plazmy, jejíž frakce může být velice nízká (až 0,01 %), je nutné klást důraz na používání vysoce senzitivních molekulárních metod. Výsledky tohoto porovnání kvality potvrzují nutnost pokusu o rebiopsii u pacientů s negativním výsledkem, neboť oproti vyšetření solidního vzorku tkáně stoupá podíl falešně negativních případů.
Background: Detection of EGFR mutations in tumor tissue represents a standard testing procedure in patients with non-small cell lung cancer. Molecular testing of circulating tumor DNA (ctDNA) in plasma enables detection of mutations in cases where tumor specimens are unavailable or when monitoring of therapeutic responses is necessary. In addition, according to the recent literature, ctDNA better reflects the heterogeneity of the neoplastic cell population than isolated tumor lesion or metastasis. We report a national interlaboratory evaluation aimed at assessing the analytical quality of ctDNA EGFR testing in plasma across seven reference laboratories in the Czech Republic. Material and methods: Aliquots of 13 plasma samples were sent to 7 laboratories and consisted of commercially available 2 ml plasma specimens of genomic DNA with mutant allelic frequencies of 5, 0.5, 0.05, and 0% of the most common sensitizing mutations (deletion in exon 19, L858R) and the resistance mutation T790M. DNA extraction and EGFR testing were performed according to standard procedures. In 6/7 laboratories the cobas® EGFR Mutation Test v2 was used. One laboratory employed the Super-ARMS® EGFR Mutation Detection Kit. Results: In total, 91 genotypes were determined with an overall error rate of 24.2% (22/91). The overall error rates were 3.2% (2/63) for the 0.5% mutation frequency and 0% for the 5% mutation frequency (0/35), respectively. No false positive results were reported. The cobas® method achieved consistent results with the 0.05% mutation frequency for the exon 19 deletion. For L858R and T790M mutations, the threshold was above the 0.5% frequency. Conclusions: The results show that EGFR testing for ctDNA in plasma has limited sensitivity, especially for detection of the T790M mutation. Particularly, in ctDNA testing of very low mutated DNA plasma fractions (below 0.01%), emphasis should be placed on the use of highly sensitive molecular methods. The outcomes of this quality assessment confirm the need for rebiopsy in patients with negative plasma results because of a higher false negative rate in comparison to tissue testing.
