Κυριακή 1 Δεκεμβρίου 2019



Genetic and Clinical Profile of Chinese Patients with Autosomal Dominant Spastic Paraplegia

Abstract

Background

Hereditary spastic paraplegia (HSP) refers to a group of neurodegenerative disorders characterized by bilateral weakness, spasticity, and hyperreflexia in the lower limbs. The autosomal dominant HSP (ADHSP) predominantly presents as the pure form, but the clinical profiles and causal genetic variants underlying ADHSP are complex, and many remain unknown.

Methods

A cohort of 15 Chinese HSP pedigrees (including 35 patients and their 22 relatives) were screened by multiplex ligation-dependent probe amplification (MLPA) or whole-exome sequencing (WES). Neurological assessments were also conducted.

Results

The main subtypes of HSP above detected in our cohort were SPG4, SPG3A, and SPG6. Fifteen HSP-inducing mutations were identified, among which six were novel mutations: SPAST c.1277T>C, c.1292G>C, c.1562T>C, and c.1693A>T, NIPA1 c.748A>C, and KIDINS220 c.4448C>G. As expected, the most common presentation of the ADHSP cases was the pure form, manifesting spasticity of lower limbs and hyperreflexia, as well as pyramidal signs. Differing substantially from previous reports for KIDINS220 variants, our study family exhibited autosomal dominant inheritance, and only presented with spastic paraplegia, with no signs of intellectual disability, nystagmus, or obesity.

Conclusion

Our work reveals a non-classical spastic paraplegia, intellectual disability, nystagmus, and obesity phenotype for a KIDINS220 mutation, which broadens both the clinical and genetic spectrum for ADHSP. Beyond underscoring the utility of using both MLPA and WES in studies of HSP, our work deepens the scientific understanding of phenotypes for ADHSP and defines new genetic variants to facilitate future diagnoses.

FebriDx ® : A Rapid Diagnostic Test for Differentiating Bacterial and Viral Aetiologies in Acute Respiratory Infections

Abstract

FebriDx® is a rapid, point-of-care diagnostic test that is designed to aid in the differentiation of bacterial and viral acute respiratory infections (ARIs), thus helping to guide decisions regarding the prescription of antibiotics in the outpatient setting. FebriDx carries a CE mark for use in the EU and is also approved in several other countries, including Canada, Saudi Arabia and Singapore. It is indicated for use in patients > 2 years old with symptoms consistent with a community-acquired ARI. The test involves the use of an immunoassay on a fingerstick blood sample to provide simultaneous, qualitative measurement of elevated levels of C-reactive protein (CRP) and myxovirus resistance protein A (MxA). In two prospective, multicentre studies in patients with acute upper respiratory tract infections, FebriDx was shown to be both sensitive and specific in identifying patients with a clinically significant infection and in differentiating between infections of bacterial and viral aetiology. The test is simple, requires no additional equipment and produces actionable results in ~ 10 min. As was demonstrated in a small, retrospective analysis, FebriDx results can help guide (improve) antibiotic prescribing decisions. Reducing the unnecessary or inappropriate prescription of antibiotics for ARIs of probable viral aetiology is important for antibiotic stewardship and can also reduce the unnecessary exposure of patients to the risk of antibiotic-related adverse events. FebriDx thus represents a useful diagnostic tool in the outpatient setting.

Expression Profile of Markers for Targeted Therapy in Gastric Cancer Patients: HER-2, Microsatellite Instability and PD-L1

Abstract

Background

The assessment of human epidermal growth factor receptor 2 (HER2), microsatellite instability (MSI) and programmed cell death-ligand 1 (PD-L1) expression is relevant for the selection and effectiveness of targeted therapy in gastric cancer (GC).

Objective

We aimed to investigate the clinicopathological characteristics and prognosis of GC patients according to these profiles.

Methods

GC patients who underwent gastrectomy with D2 lymphadenectomy were eligible. HER2, MSI status and PD-L1 expression were analyzed by immunohistochemistry (IHC). Patients were grouped as follows: HER2+ group, immunotherapy (IT) group (MSI and/or PD-L1+), and non-targeted therapy (NTT) group (stable microsatellite and HER2/PD-L1−).

Results

Among 282 patients, 50 (17.7%) were HER2+ and 79 (28%) MSI/PD-L1+. Fifteen had HER2+ and MSI/PD-L1+, while 168 (59.6%) were in the NTT group. HER2+ GCs were related to male gender (p = 0.007), intestinal type (p = 0.001) and less advanced pTNM stage (p = 0.029). Older age (p = 0.003), subtotal gastrectomy (p = 0.025), intestinal type (p = 0.008), pN0 status (p = 0.002) and less advanced pTNM stage (p = 0.001) were associated with the IT group. IT GC had better disease-free survival (DFS) and overall survival than the NTT group (p = 0.015 and p = 0.027, respectively). Concerning patients eligible for the standard adjuvant therapy, the treatment impacted positively on DFS for HER2+ and NTT groups (p = 0.003 and p = 0.042, respectively). No difference in DFS was seen between IT patients who received perioperative/adjuvant therapy and those treated only with surgery (p = 0.160).

Conclusions

GC patients who exhibited markers that can serve as an indication for known targeted therapy represent 40.4% of cases. The IT group was associated with a better prognosis. No benefit with standard adjuvant treatment appears to be achieved in MSI/PD-L1+ GCs.

Loop Mediated Isothermal Amplification: A Promising Tool for Screening Genetic Mutations

Abstract

Mutation screening is elemental for clinical diagnosis and in determining therapeutic strategies. Nucleic acid-based techniques are considered to be the most accurate tools in genetic diagnosis. One such technique is loop-mediated isothermal amplification (LAMP) assay, which has seen tremendous applications in recent years. The advantages of the assay lie in its rapidity, efficiency, sensitivity, and cost. It works in isothermal conditions and amplifies the target gene using DNA polymerases that have strand displacement activity. To date, the assay has been widely used in different fields of research, including pathogen detection, crop development, and disease diagnosis. However, despite the potential, its application in mutation screening has been minimal. This review highlights the LAMP assay and its variants that have been developed for screening single-nucleotide polymorphisms and gene translocations in cancer.

Clinical Validation and Implementation of a Measurable Residual Disease Assay for NPM1 in Acute Myeloid Leukemia by Error-Corrected Next-Generation Sequencing

Abstract

Background

Nucleophosmin 1 (NPM1) is one of the most commonly mutated genes in acute myeloid leukemia, with mutations observed in approximately 30% of all adult cases. The persistence of NPM1 mutations following chemotherapy is associated with a greater risk of relapse as well as a lower rate of survival, making NPM1 measurable residual disease (MRD) an informative clinical target.

Methods

Herein, we have developed a straightforward unique molecular identifier (UMI)-based amplicon next-generation sequencing method for the detection of NPM1-mutated MRD that addresses some of the limitations present in other assays.

Results

The NPM1 assay allowed for accurate counting of individual mutant and wild-type molecules down to 0.01% variant allelic frequency. In silico contamination experiments highlighted the ability of this UMI methodology to maximize specificity through dramatic reductions in sequencing/demultiplexing bleed-through error.

Conclusion

Performance and clinical utility of the NPM1 MRD assay are established via both validation experiments and analyses of live performance over 1.5 years of routine clinical service.

The Long Non-Coding RNA Landscape of Atherosclerotic Plaques

Abstract

Currently, cardiovascular diseases continue to be the leading cause of death worldwide; therefore, atherosclerosis remains one of the most crucial public health problems. This chronic and complex disease is considered to be a result of aberrant lipid homeostasis and inflammation of the inner wall of arteries that leads to plaque development. In recent years, a specific class of non-coding RNAs that are characterised by transcript lengths longer than 200 nucleotides, called long non-coding RNAs (lncRNAs), has emerged. Moreover, a growing body of evidence indicates that deregulation of lncRNA expression may contribute to the development of many diseases. Despite continuous efforts in deciphering the molecular basis of atherosclerotic plaque (AP) formation, many aspects of this process remain elusive. Therefore, continuing efforts in this area should remain the highest priority in the coming years. Establishment of a standardised experimental pipeline and validation of lncRNAs as possible relevant biomarkers for cardiovascular disease would enable the translation of gathered findings into clinical practice.

Clinical Implications of Chromosomal Instability (CIN) and Kinetochore Abnormalities in Breast Cancers

Abstract

Genetic instability is a defining property of cancer cells and is the basis of various lesions including point mutations, copy number alterations and translocations. Chromosomal instability (CIN) is part of the genetic instability of cancer and consists of copy number alterations in whole or parts of cancer cell chromosomes. CIN is observed in differing degrees in most cancers. In breast cancer, CIN is commonly part of the genomic landscape of the disease and has a higher incidence in aggressive sub-types. Tumor suppressors that are commonly mutated or disabled in cancer, such as p53 and pRB, play roles in protection against CIN, and as a result, their dysfunction contributes to the establishment or tolerance of CIN. Several structural and regulatory proteins of the centromeres and kinetochore, the complex structure that is responsible for the correct distribution of genetic material in the daughter cells during mitosis, are direct or, mostly, indirect transcription targets of p53 and pRB. Thus, despite the absence of structural defects in genes encoding for centromere and kinetochore components, dysfunction of these tumor suppressors may have profound implications for the correct function of the mitotic apparatus contributing to CIN. CIN and its prognostic and therapeutic implications in breast cancer are discussed in this article.

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