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European Journal of Human Genetics :... Jun 2021Since a substantial difference in the prevalence of genetic causes of rod-cone dystrophy (RCD) was found among different populations, we conducted a systematic review of...
Since a substantial difference in the prevalence of genetic causes of rod-cone dystrophy (RCD) was found among different populations, we conducted a systematic review of the genetic findings associated with RCD in Arab countries. Of the 816 articles retrieved from PubMed, 31 studies conducted on 407 participants from 11 countries were reviewed. Next-generation sequencing (NGS) was the most commonly used technique (68%). Autosomal recessive pattern was the most common pattern of inheritance (97%) and half of the known genes associated with RCD (32/63) were identified. In the Kingdom of Saudi Arabia, in addition to RP1 (20%) and TULP1 (20%), gene defects in EYS (8%) and CRB1 (7%) were also prevalently mutated. In North Africa, the main gene defects were in MERTK (18%) and RLBP1 (18%). Considering all countries, RP1 and TULP1 remained the most prevalently mutated. Variants in TULP1, RP1, EYS, MERTK, and RLBP1 were the most prevalent, possibly because of founder effects. On the other hand, only ten Individuals were found to have dominant or X-linked RCD. This is the first time a catalog of RCD genetic variations has been established in subjects from the Arabi countries. Although the last decade has seen significant interest, expertise, and an increase in RCD scientific publication, much work needs to be conducted.
Topics: Carrier Proteins; Cone-Rod Dystrophies; Eye Proteins; Female; Gene Frequency; Genetic Heterogeneity; Genetic Testing; Humans; Male; Microtubule-Associated Proteins; Middle East; Mutation; c-Mer Tyrosine Kinase
PubMed: 33188265
DOI: 10.1038/s41431-020-00754-0 -
Frontiers in Neurology 2020Tau protein, a neuronal microtubule-associated protein, becomes hyperphosphorylated in several neurodegenerative diseases called tauopathies. Hyperphosphorylation of tau...
Similarities and Differences in the Pattern of Tau Hyperphosphorylation in Physiological and Pathological Conditions: Impacts on the Elaboration of Therapies to Prevent Tau Pathology.
Tau protein, a neuronal microtubule-associated protein, becomes hyperphosphorylated in several neurodegenerative diseases called tauopathies. Hyperphosphorylation of tau is correlated to its redistribution from the axon to the somato-dendritic compartment at early stages of tauopathies. Interestingly, tau hyperphosphorylation begins in different regions of the brain in each tauopathy. In some regions, both neurons and glial cells develop tau hyperphosphorylation. Tau hyperphosphorylation is also observed in physiological conditions such as hibernation and brain development. In the first section of present article, we will review the spatiotemporal and cellular distribution of hyperphosphorylated tau in the most frequent tauopathies. In the second section, we will compare the pattern of tau hyperphosphorylation in physiological and pathological conditions and discuss the sites that could play a pivotal role in the conversion of non-toxic to toxic forms of hyperphosphorylated tau. Furthermore, we will discuss the role of hyperphosphorylated tau in physiological and pathological conditions and the fact that tau hyperphosphorylation is reversible in physiological conditions but not in a pathological ones. In the third section, we will speculate how the differences and similarities between hyperphosphorylated tau in physiological and pathological conditions could impact the elaboration of therapies to prevent tau pathology. In the fourth section, the different therapeutic approaches using tau as a direct or indirect therapeutic target will be presented.
PubMed: 33488502
DOI: 10.3389/fneur.2020.607680 -
Frontiers in Bioscience (Landmark... Jan 2024Microtubule-associated protein tau () mutations are one of the main causes of genetic Frontotemporal dementia (FTD) and are characterised by high clinical heterogeneity....
BACKGROUND
Microtubule-associated protein tau () mutations are one of the main causes of genetic Frontotemporal dementia (FTD) and are characterised by high clinical heterogeneity. A behavioural variant of FTD is the principal phenotype, but other rarer phenotypes are described, mostly reported as single cases. In this review, we provide an overview of the clinical phenotypes associated with mutations in order to define their characteristics and explore genotype-phenotype correlations.
METHODS
We performed systematic bibliographic research on the Pubmed database, focusing on articles published between 1998 and 2022. We analysed the clinical phenotype of 177 patients carrying mutations, focusing on the rarest ones. We performed a narrative synthesis of the results.
RESULTS
Regarding language phenotypes, the most frequent were the non-fluent variant and the semantic variant of Primary Progressive Aphasia (nfvPPA, svPPA), approximately in the same proportion. Almost 20% of the whole group of patients present a clinical phenotype belonging to the corticobasal syndrome-progressive supranuclear palsy (CBS-PSP) spectrum. While no clear genotype-phenotype correlation could be identified, some mutations were associated with a specific phenotype, while others gave origin to multiple clinical pictures and mixed phenotypes.
CONCLUSIONS
A high clinical heterogeneity exists in FTD associated with mutations without a clear phenotype-genotype correlation in most cases. However, some characteristics can be helpful to drive genetic testing. Deep phenotyping of patients, together with functional studies of single mutations, particularly those associated with atypical phenotypes, are necessary to better understand the biological mechanisms underlying this clinical variability.
Topics: Humans; Frontotemporal Dementia; tau Proteins; Mutation; Genetic Association Studies; Phenotype
PubMed: 38287807
DOI: 10.31083/j.fbl2901012