Wide access to clinical exome/genome sequencing (ES/GS) enables the identification of multiple molecular diagnoses (MMDs), being a long-standing but underestimated concept, defined by two or more ...causal loci implicated in the phenotype of an individual with a rare disease. Only few series report MMDs rates (1.8% to 7.1%). This study highlights the increasing role of MMDs in a large cohort of individuals addressed for congenital anomalies/intellectual disability (CA/ID).
From 2014 to 2021, our diagnostic laboratory rendered 880/2658 positive ES diagnoses for CA/ID aetiology. Exhaustive search on MMDs from ES data was performed prospectively (January 2019 to December 2021) and retrospectively (March 2014 to December 2018).
MMDs were identified in 31/880 individuals (3.5%), responsible for distinct (9/31) or overlapping (22/31) phenotypes, and potential MMDs in 39/880 additional individuals (4.4%).
MMDs are frequent in CA/ID and remain a strong challenge. Reanalysis of positive ES data appears essential when phenotypes are partially explained by the initial diagnosis or atypically enriched overtime. Up-to-date clinical data, clinical expertise from the referring physician, strong interactions between clinicians and biologists, and increasing gene discoveries and improved ES bioinformatics tools appear all the more fundamental to enhance chances of identifying MMDs. It is essential to provide appropriate patient care and genetic counselling.
Up to 80% of BRCA1 and BRCA2 genetic variants remain of uncertain clinical significance (VUSs). Only variants classified as pathogenic or likely pathogenic can guide breast and ovarian cancer ...prevention measures and treatment by PARP inhibitors. We report the first results of the ongoing French national COVAR (cosegregation variant) study, the aim of which is to classify BRCA1/2 VUSs. The classification method was a multifactorial model combining different associations between VUSs and cancer, including cosegregation data. At this time, among the 653 variants selected, 101 (15%) distinct variants shared by 1,624 families were classified as pathogenic/likely pathogenic or benign/likely benign by the COVAR study. Sixty-six of the 101 (65%) variants classified by COVAR would have remained VUSs without cosegregation data. Of note, among the 34 variants classified as pathogenic by COVAR, 16 remained VUSs or likely pathogenic when following the ACMG/AMP variant classification guidelines. Although the initiation and organization of cosegregation analyses require a considerable effort, the growing number of available genetic tests results in an increasing number of families sharing a particular variant, and thereby increases the power of such analyses. Here we demonstrate that variant cosegregation analyses are a powerful tool for the classification of variants in the BRCA1/2 breast-ovarian cancer predisposition genes.
Epidemiological reports and studies using rodent models indicate that early exposure to nutrient and/or hormonal challenges can reprogram metabolism at adulthood. Hypothalamic arcuate nucleus (ARC) ...integrates peripheral and central signals to adequately regulate energy homeostasis. microRNAs (miRNAs) participate in the control of gene expression of large regulatory networks including many signaling pathways involved in epigenetics regulations. Here, we have characterized and compared the miRNA population of ARC of adult male rats continuously exposed to a balanced metabolic environment to the one of adult male rats exposed to an unbalanced high-fat/high-carbohydrate/moderate-protein metabolic environment during the perinatal period and/or at adulthood that consequently displayed hyperinsulinemia and/or hyperleptinemia. We identified more than 400 miRNA species in ARC of adult male rats. By comparing the miRNA content of six biological replicates in each of the four perinatal/adult environments/rat groups, we identified the 10 miRNAs specified by clusters miR-96/182/183, miR-141/200c, and miR-200a/200b/429 as miRNAs of systematic and uncommonly high variation of expression. This uncommon variation of expression may underlie high individual differences in aging disease susceptibilities. By comparing the miRNA content of the adult ARC between the rat groups, we showed that the miRNA population was not affected by the unbalanced adult environment while, in contrast, the expression of 11 miRNAs was repeatedly impacted by the perinatal unbalanced environment. Our data revealed a miRNA response of adult ARC to early metabolic environmental challenge.
MicroRNAs (miRNAs) modulate gene expression in male germ cells and somatic tissues of mammals on a genome-wide scale. Hundreds of miRNAs are encoded by mammalian genomes, a large fraction of which is ...expressed in brain. Here we have investigated the complexity and dynamics of miRNA transcriptomes that associate with neuronal network maturation of hypothalamic arcuate nucleus and median eminence (ARC/ME) in rat by analysing more than 300 miRNAs from 3-7 biological replicates at 5 postnatal time-points. The network connecting ARC/ME to other hypothalamic and extra-hypothalamic regions maturates in an environment-dependent manner. We therefore analyzed miRNA transcriptomes of progeny of dams fed either a balanced or unbalanced diet during gestation and lactation. More than 30% of the miRNAs displayed significative changes of expression between stages P8 and P14, and P21 and P28; half of the changes were greater than 3-fold. Among those miRNAs were well-known and dozens of still poorly documented miRNAs. Progeny of dams fed an unbanced diet displayed a severe growth retardation phenotype, lower levels of plasma leptin but almost identical miRNA transcriptomes. Together these data demonstrate that two substantial and robust changes in miRNA transcriptome of ARC/ME occur at a period crucial for neuronal network functional organization.
New Findings
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What is the topic of this review? We sought to establish a high number of microRNA expression profiles of individual hypothalamic nuclei of single rats.
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What advances does it ...highlight? This can be achieved at a cost compatible with laboratory finance by using tagged cDNA libraries constructed from purified small RNAs and a multiplex sequencing strategy.
Integrative research has taken on the challenge of addressing questions in physiology by using novel knowledge and novel techniques. Recently, small and long non‐coding RNAs have emerged as key regulators of gene expression, while next‐generation sequencing technologies have revolutionized the characterization of genomes and gene expression. For a decade, it has been known that microRNAs (miRNAs) are RNAs of 18–24 bases that regulate gene expression in mammals. Here, we first describe the nature of miRNAs and the advantages of high‐throughput sequencing technologies for establishing miRNA expression profiles. The hypothalamus harbours a dozen specialized areas or nuclei, the sampling of which is required to establish physiologically relevant miRNA expression profiles. MicroRNA expression profiling from single animals is also important for investigating potential genetic or epigenetic differences between individuals. Establishing a large number of miRNA expression profiles of individual hypothalamic nuclei of single rats at a cost compatible with laboratory finance can be achieved by using tagged cDNA libraries constructed from purified small RNAs and a multiplex sequencing strategy. We continue this report by surveying specificities of the different strategies that are used at present for constructing tagged cDNA libraries and provide a comparative analysis of miRNA expression profiles from hypothalamic arcuate nuclei of seven male Wistar rats.
In order to determine the effect of different image compounding functions on perceived image quality, 84 pairs of ultrasound images were collected, mixed, and reviewed by four independent observers ...who were asked to identify the highest quality image of each pair. Each image in a pair was made using the same orientation, transducer, frequency, and gain settings but different compounding settings. Outcomes were analyzed using logistic regression. Observers judged compound images to be better quality than noncompound images in 69% cases, the same quality in 24%, and poorer quality in 7%. Overall, compound images were considered significantly better quality than noncompound images (P<0.001). Compound images were more likely to be considered better quality than the corresponding noncompound images when combined transmit/receive spatial compounding was used rather than receive-only spatial compounding or transmit compounding, and when the vector transducer or the curvilinear transducer were used rather than the linear transducer. Observers considered improved border definition and increased signal to noise ratio to be the properties that accounted most often for higher quality of compound images compared with noncompound images.
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