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117 records · Page 7Linked to original sources

From the Microscope to the Genome: A New Era in the Molecular Genetics of Epidermolysis Bullosa.

Epidermolysis bullosa (EB) is a heterogeneous group of inherited disorders characterised by skin fragility, caused by pathogenic variants in genes encoding structural components of the dermo-epidermal junction. With the advent of next-generation sequencing (NGS), the diagnostic paradigm has shifted from a morphological to a genotype-oriented approach. This review summarises the genetic architecture of EB, the types of mutations and genotype-phenotype relationships, the challenges in interpreting variants of unknown significance (VUS), and therapeutic strategies targeting specific mutational mechanisms, including read-through approaches, exon skipping and genome editing. The role of modifier genes and epigenetic factors in clinical variability is also discussed. The focus is on the translational potential of genomics for personalized therapy in EB. Overall, this review synthesizes the molecular basis of all four major EB types across 16+ classical genes, highlights the paradigm shift where NGS achieves a diagnostic yield exceeding 90%, and critically assesses recent therapeutic milestones-ranging from the first FDA-approved topical gene therapy to precision RNA and genome-editing modalities.

Humans↗

Whole-exome Sequencing Identifies Novel Candidate PCNT Variants in a Child With Overlapping MOPD II Features: A Case Report.

A 7-year-old Chinese boy presented with severe postnatal growth failure (height <3rd percentile at age 7 years), global developmental delay, moderate intellectual disability, and characteristic dysmorphic features including hypertelorism, short palpebral fissures, low-set ears, and a broad nasal bridge. A single electrocardiogram demonstrated a borderline corrected QT interval (QTc = 450 ms). No arrhythmias, QT-prolonging medications, electrolyte abnormalities, or relevant family cardiac history were identified. This finding warrants longitudinal cardiology follow-up and should not be interpreted as definitive Long QT syndrome. Whole-exome sequencing identified two novel missense variants in the PCNT gene (NM_006031.5): c.5675A>G (p.Glu1892Gly) in exon 28 and c.9734G>T (p.Arg3245Ile) in exon 45. Both variants were absent from gnomAD, ExAC, the 1000 Genomes Project database, and Chinese population databases, fulfilling ACMG criterion PM2. Although classified as variants of uncertain significance (VUS) because of limited functional evidence and conflicting in silico predictions, the variants occur in a gene associated with primordial dwarfism and are accompanied by partial phenotypic overlap with Microcephalic Osteodysplastic Primordial Dwarfism Type II (MOPD II). However, parental segregation analysis was unavailable; therefore, the variant phase could not be confirmed, and a recessive disease mechanism could not be established. These findings support the presence of candidate PCNT variants in an atypical primordial dwarfism phenotype and illustrate the utility of whole-exome sequencing for generating testable molecular hypotheses in genetically heterogeneous growth disorders. A definitive molecular diagnosis cannot be established at present, and the isolated borderline QTc finding requires further clinical evaluation.

Humans↗

'Truthsets' for clinical validation of large-scale functional assays: Practice recommendations from Cancer Variant Interpretation Group UK (CanVIG-UK).

BACKGROUND: Large-scale functional assays, including multiplex assays of variant effect, have substantial potential to resolve variants of uncertain significance (VUS), particularly for rare missense variants where clinical and population evidence are limited. The ClinGen assay-level clinical validation framework described by Brnich et al provided baseline guidance for the use of functional data for variant classification. However, clear consensus regarding construction of variant 'truthsets' by which to clinically validate functional data remains lacking. METHODS: CanVIG-UK developed consensus recommendations for truthset construction through an iterative national consultation process involving the CanVIG Steering Advisory Group (CStAG), wider CanVIG-UK membership, and engagement with international functional genomics experts. Consultation was based on previous analyses of 2,120 truthset constructions examining the impact of truthset composition on evidence point allocation within the ClinGen assay-level clinical validation framework. RESULTS: Across several consultations, CanVIG-UK established nine guiding principles and seven best-practice recommendations for assay-level clinical validation, using the assumed context of an assay for a cancer susceptibility gene where loss-of-function is the mechanism of pathogenicity. The principal recommendation stipulates, where assays are intended for use in interpretation of largely missense variants, the truthset used to validate should comprise only missense variants. Rather than mixtures of different variant types which may serve to over-estimate assay performance. Additional recommendations support option for relaxation of truthset stringency to improve power, augmentation of benign missense truthsets with systematically derived 'proxy-clinical' benign variants, independent clinical validation separate from assayist-defined validation, and careful evaluation of missense score distributions against that of protein-truncating and synonymous variants. Guidance is also provided for scenarios with limited pathogenic truthset availability and for assays reporting multiple deleterious zones or readouts. CONCLUSIONS: The CanVIG-UK principles and recommendations for truthset construction upon the ClinGen assay-level clinical validation framework, while aiming to form a baseline for future discussion regarding other functional and disease contexts and helping to address the gap between publication of new data and routine clinical implementation.

Journal Article↗

The effects of calcium on smooth muscle mechanics and energetics.

In smooth muscle isometric force, shortening velocity, the ATP utilization under isometric conditions, and tension cost are all functions of calcium. This suggests that both cross bridge number and cycle rate are dependent on calcium. On the other hand, the series elastic component does not exhibit a significant dependence on calcium under conditions in which Vus can be increased with little change in Fo. And although the data is not as extensive, the efficiency in working producing contractions is not a strong function of calcium. Our challenge is to fit these mechanical and energetic data into a mechanism which fits the ever growing and controversial body of evidence on the biochemical basis for the action of calcium on the contractile apparatus. At present the most striking feature is the observation that calcium can control the velocity in a manner which is independent of isometric force and efficiency. This would appear to favor a mechanism in which calcium directly affected cross bridge cycle rate in the absence of an internal load.

Adenosine Triphosphate↗

Genetic testing and reporting: What the endocrinologists should know and can expect (Joint position paper of the ENDO-ERN).

Over the last decade, next generation sequencing (NGS) has become an essential tool for diagnostic DNA testing in human genetics. To improve the understanding of available genetic testing strategies and to facilitate the request of genetic testing in daily endocrine practice, clinical and laboratory experts in the field have summarized the major issues which should be known and considered. In this joint position paper of the ENDO-ERN, the roles and responsibilities of the health care professionals involved in the diagnostic workflow are described, and the major issues concerning genetic testing workflows are overviewed. These issues encompass all relevant steps, including test request and pre-analytical procedures, laboratory and data processing workflows, quality assurance, and reporting. As NGS procedures result in an increasing number of variants of unknown significance and incidental findings, these aspects are addressed as well. Accompanied by illustrations of the genetic diagnostic workflow and of concise reports for a fast orientation about the major aspects of genetic testing, this joint paper should support the health care professionals during a request for genetic testing.

VUS↗

Characterization of a Novel BTD Hypomorphic Variant in a Patient with Complex Neurodevelopmental Delay: Resolving Actionable Metabolic Vulnerabilities Beyond Borderline Plasma Biochemistry.

Plasma biochemistry often presents significant limitations in diagnosing borderline metabolic disorders, particularly within complex neurodevelopmental phenotypes. Here, we present the clinical genomic evaluation of a six-year patient presenting with early-onset hypotonia and severe gastrointestinal complications whose newborn screening panel did not evaluate biotinidase (BTD) activity. While initial baseline plasma biochemistry yielded borderline residual BTD function (46% of the population mean), targeted sequencing identified a novel, compound heterozygous hypomorphic variant (p.Thr459Met) in trans with the common p.Asp424His allele. In vitro functional validation confirmed that p.Thr459Met induces severe protein misfolding and intracellular retention, impairing enzyme secretion. Biotin supplementation triggered a documented and favorable therapeutic improvement, establishing this borderline enzymatic background as an actionable metabolic vulnerability unmasked by chronic gastrointestinal stressors. This study underscores the critical value of functional genomic characterization over static enzymatic biomarkers to identify highly treatable metabolic components within heterogeneous clinical landscapes.

Humans↗

[Experimental data on the hygienic regulation of dimethyl phosphite in the air of a work area].

Dimethylphosphite, being a semiproduct of chlorophosphonium synthesis, is a moderately toxic substance according to the criterion of acute toxicity. It is characterized by marked cumulative properties, absorption from skin and local irritative action. Acute and chronic poisoning induces disorders of the nervous system. MAC in the air is 0.5 mg/m3 as established by Ministry of Health.

Air Pollutants, Occupational↗

[Chromatography of thrombin and antithrombin III on biospecific silochromes].

It was shown that the seaweed sulfopolysaccharides Furcellaria and Phyllophora--furcellaran and phyllophoran--are the competitive inhibitors of thrombin-induced fibrinogen clotting. Biospecific adsorbents for thrombin and antithrombin III (AT III) isolation were synthesized with heparin, phyllophoran and furcellaran as ligands on aminopropylsilochrome and this proteins sorption characteristics on this sorbents in comparisons with heparin-cellulose and heparin-sepharose were investigated. Possible application of the synthesized adsorbents both for thrombin, AT III purification from blood products and for alpha-thrombin, beta and gamma-thrombin separation are discussed.

Alginates↗