35 research outputs found

    Assessment of parental mosaicism rates in neurodevelopmental disorders caused by apparent de novo pathogenic variants using deep sequencing

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    Abstract While de novo variants (DNV) are overall at low risk of recurrence in subsequent pregnancies, a subset is at high risk due to parental mosaicism. Accurately identifying cases of parental mosaicism is therefore important for genetic counseling in clinical care. Some studies have investigated the rate of parental mosaics, but most were either limited by the sensitivity of the techniques (i.e. exome or genome sequencing), or focused on specific types of disease such as epileptic syndromes. This study aimed to determine the proportion of parental mosaicism among the DNV causing neurodevelopmental disorders (NDDs) in a series not enriched in epilepsy syndromes. We collected 189 patients with NDD-associated DNV. We applied a smMIP enrichment method and sequenced parental blood DNA samples to an average depth of 7000x. Power simulation indicated that mosaicism with an allelic fraction of 0.5% would have been detected for 87% of positions with 90% power. We observed seven parental mosaic variants (3.7% of families), of which four (2.1% of families) had an allelic fraction of less than 1%. In total, our study identifies a relatively low proportion of parental mosaicism in NDD-associated DNVs and raises the question of a biological mechanism behind the higher rates of parental mosaicism detected in other studies, particularly those focusing on epileptic syndromes

    Efficiency of physiotherapy with Caycedian Sophrology on children with asthma: A randomized controlled trial

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    International audienceBackground: Asthma is the most common chronic disease in pediatrics. Along with the usual drug therapy using corticosteroids and bronchodilators, some interest has been shown for adjuvant therapies, such as sophrology. However, the level of evidence for non‐pharmaceutical therapies in asthma remains low, especially in children. This study aimed to assess whether in children with asthma, peak expiratory flow (PEF) improved more after a sophrology session alongside standard treatment than after standard treatment alone.Methods: We carried out a prospective randomized controlled clinical trial among 74 children aged 6‐17 years old, hospitalized for an asthma attack. Group 1: conventional treatment (oxygen, corticosteroids, bronchodilators, physiotherapy) added to one session of sophrology. Group 2: conventional treatment alone. The primary outcome was the PEF variation between the initial and final evaluations (PEF2‐PEF1).Results: Demographic and clinical characteristics were similar in both groups at baseline. Measures before and after the sophrology session showed that the PEF increased by mean 30 L/min in the sophrology group versus 20 L/min in the control group (P = 0.02). Oxygen saturation increased by 1% versus 0% (P = 0.02) and the dyspnea score with visual analogue scale improved by two points point (P = 0.01). No differences were observed between the two groups in terms of duration of hospitalization, use and doses of conventional medical treatment (oxygen, corticosteroids, and bronchodilators), and quality of life scores.Conclusions: Sophrology appears as a promising adjuvant therapy to current guideline‐based treatment for asthma in children

    A large fraction of unclassified variants of the mismatch repair genes MLH1 and MSH2 is associated with splicing defects

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    International audienceNumerous unclassified variants (UVs) have been found in the mismatch repair genes MLH1 and MSH2 involved in hereditary nonpolyposis colorectal cancer (HNPCC or Lynch syndrome). Some of these variants may have an effect on pre‐mRNA splicing, either by altering degenerate positions of splice site sequences or by affecting intronic or exonic splicing regulatory sequences such as exonic splicing enhancers (ESEs). In order to determine the consequences of UVs on splicing, we used a functional assay of exon inclusion. For each variant, mutant and wild‐type exons to be tested were PCR‐amplified from patient genomic DNA together with ∌150 bp of flanking sequences and were inserted into a splicing reporter minigene. After transfection into HeLa cells, the effects on splicing were evaluated by RT‐PCR analysis and systematic sequencing. A total of 22 UVs out of 85 different variant alleles examined in 82 families affected splicing, including four exonic variants that affected putative splicing regulatory elements. We analyzed short stretches spanning the latter variants by cloning them into the ESE‐dependent central exon of a three‐exon splicing minigene and we showed in cell transfection experiments that the wild‐type sequences indeed contain functional ESEs. We then used this construct to query for ESE elements in the MLH1 or MSH2 regions affected by 14 previously reported exonic splicing mutations and showed that they also contain functional ESEs. These splicing assays represent a valuable tool for the interpretation of UVs and should contribute to the optimization of the molecular diagnosis of the Lynch syndrome and of other genetic diseases

    Screening for TP53 rearrangements in families with the Li–Fraumeni syndrome reveals a complete deletion of the TP53 gene

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    International audienceThe absence of detectable germline TP53 mutations in a fraction of families with Li-Fraumeni syndrome (LFS) has suggested the involvement of other genes, but this hypothesis remains controversial. The density of Alu repeats within the TP53 gene led us to search genomic rearrangements of TP53 in families without detectable TP53 mutation. To this aim, we adapted the quantitative multiplex PCR of short fluorescent fragments (QMPSF) method to the analysis of the 11 exons of TP53. We analysed 98 families, either fulfilling (six families) or partially meeting (92 families) the criteria for LFS, and in which classical methods had failed to reveal TP53 alterations. We identified, in a large family fulfilling the criteria for LFS, a complete heterozygous deletion of TP53. Additional QMPSF analyses indicated that this deletion, which partially removed the centromeric FLJ10385 locus, covered approximately 45 kb. This deletion was shown to result from a complex rearrangement involving two distinct Alu-mediated recombinations. We conclude that TP53 germline rearrangements occur as rare events, but must be considered in LFS families without detectable point TP53 mutation

    Germline Mutations of Inhibins in Early-Onset Ovarian Epithelial Tumors

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    International audienceTo identify novel genetic bases of early-onsetepithelial ovarian tumors, we used the trio exome sequencing strategy in a patient without familial history of cancerwho presented metastatic serous ovarian adenocarcinomasat 21 years of age. We identified a single de novo mutation(c.1157A>G/p.Asn386Ser) within the INHBA gene encoding the ÎČA-subunit of inhibins/activins, which play akey role in ovarian development. In vitro, this mutation alters the ratio of secreted activins and inhibins. In a secondpatient with early-onset serous borderline papillary cystadenoma, we identified an unreported germline mutation(c.179G>T/p.Arg60Leu) of the INHA gene encoding theα-subunit, the partner of the ÎČA-subunit. This mutationalso alters the secreted activin/inhibin ratio, by disruptingboth inhibin A and inhibin B biosynthesis. In a cohort of62 cases, we detected an additional unreported germlinemutation of the INHBA gene (c.839G>A/p.Gly280Glu).Our results strongly suggest that inhibin mutations contribute to the genetic determinism of epithelial ovariantumors
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