A large cohort study of prenatal exome sequencing redefines diagnosis in fetal corpus callosum anomalies.

Anomalies of the corpus callosum (AnCC) are congenital malformations associated with highly variable neurodevelopmental outcomes. We performed prenatal Exome Sequencing (pES) on a cohort of 352 fetuses diagnosed with AnCC, analyzing the diagnostic yield, the implicated genes based on the type of anomaly (partial or complete agenesis, short corpus callosum, or callosal dysgenesis) and assessing the impact on pregnancy outcomes. The overall diagnostic yield of pES was 23%, with pathogenic or likely pathogenic variants identified in 49 different genes, most of which linked to intellectual developmental disorders.

Resolving structural variations missed by short-read sequencing uncovers their pathogenicity.

Background: Short-read genome sequencing (sr-GS) affords efficient and accurate characterisation of apparently balanced chromosomal rearrangement (ABCR) breakpoints except in 9%-11% of cases that remain undetectable.

Methods: Among 117 ABCR that we studied in patients with abnormal phenotype, 14 (11.9%) could not be detected by our current strategy including sr-GS, alignment against the GRCh38 reference genome and structural variant (SV) detection using Breakdancer V.

Chromatin environment-dependent effects of DOT1L on gene expression in male germ cells.

The H3K79 methyltransferase DOT1L is essential for multiple aspects of mammalian development where it has been shown to regulate gene expression. Here, by producing and integrating epigenomic and spike-in RNA-seq data, we decipher the molecular role of DOT1L during mouse spermatogenesis and show that it has opposite effects on gene expression depending on chromatin environment. On one hand, DOT1L represses autosomal genes that are devoid of H3K79me2 at their bodies and located in H3K27me3-rich/H3K27ac-poor environments.

Stratification of the risk of ovarian dysfunction by studying the complexity of intermediate and premutation alleles of the FMR1 gene.

FMR1 premutation female carriers are at risk of developing premature/primary ovarian insufficiency (POI) with an incomplete penetrance. In this study, we determined the CGG repeat size among 1095 women with diminished ovarian reserve (DOR) / POI and characterized the CGG/AGG substructure in 44 women carrying an abnormal FMR1 repeat expansion number, compared to a group of 25 pregnant women carrying an abnormal FMR1 CGG repeat size. Allelic complexity scores of the FMR1 gene were calculated and compared between the two groups.

Assortative mating and parental genetic relatedness contribute to the pathogenicity of variably expressive variants.

We examined more than 97,000 families from four neurodevelopmental disease cohorts and the UK Biobank to identify phenotypic and genetic patterns in parents contributing to neurodevelopmental disease risk in children. We identified within- and cross-disorder correlations between six phenotypes in parents and children, such as obsessive-compulsive disorder (R = 0.32-0.

NOBOX gene variants in premature ovarian insufficiency: ethnicity-dependent insights.

Purpose: Premature ovarian insufficiency (POI) affects approximately 1% of women before the age of 40. Genetic contribution is a significant component of POI. The NOBOX gene was considered one of the major genetic causes of POI.

Assortative mating and parental genetic relatedness drive the pathogenicity of variably expressive variants.

We examined more than 38,000 spouse pairs from four neurodevelopmental disease cohorts and the UK Biobank to identify phenotypic and genetic patterns in parents associated with neurodevelopmental disease risk in children. We identified correlations between six phenotypes in parents and children, including correlations of clinical diagnoses such as obsessive-compulsive disorder (R=0.31-0.

DOT1L regulates chromatin reorganization and gene expression during sperm differentiation.

Spermatozoa have a unique genome organization. Their chromatin is almost completely devoid of histones and is formed instead of protamines, which confer a high level of compaction and preserve paternal genome integrity until fertilization. Histone-to-protamine transition takes place in spermatids and is indispensable for the production of functional sperm.

Contribution of whole genome sequencing in the molecular diagnosis of mosaic partial deletion of the NF1 gene in neurofibromatosis type 1.

Neurofibromatosis type 1 (NF1) is an autosomal dominant disease with complete penetrance but highly variable expressivity. In most patients, Next Generation Sequencing (NGS) technologies allow the identification of a loss-of-function pathogenic variant in the NF1 gene, a negative regulator of the RAS-MAPK pathway. We describe the 5-year diagnosis wandering of a patient with a clear NF1 clinical diagnosis, but no molecular diagnosis using standard molecular technologies.

Structure of mammalian Mediator complex reveals Tail module architecture and interaction with a conserved core.

The Mediator complex plays an essential and multi-faceted role in regulation of RNA polymerase II transcription in all eukaryotes. Structural analysis of yeast Mediator has provided an understanding of the conserved core of the complex and its interaction with RNA polymerase II but failed to reveal the structure of the Tail module that contains most subunits targeted by activators and repressors. Here we present a molecular model of mammalian (Mus musculus) Mediator, derived from a 4.

Multi-omic analysis of gametogenesis reveals a novel signature at the promoters and distal enhancers of active genes.

Epigenetic regulation of gene expression is tightly controlled by the dynamic modification of histones by chemical groups, the diversity of which has largely expanded over the past decade with the discovery of lysine acylations, catalyzed from acyl-coenzymes A. We investigated the dynamics of lysine acetylation and crotonylation on histones H3 and H4 during mouse spermatogenesis. Lysine crotonylation appeared to be of significant abundance compared to acetylation, particularly on Lys27 of histone H3 (H3K27cr) that accumulates in sperm in a cleaved form of H3.

MET overexpression and activation favors invasiveness in a model of anaplastic thyroid cancer.

In thyroid cancers, MET receptor overexpression has been associated with higher risk of metastatic progression. In this study, it was shown that the anaplastic thyroid cancer (ATC)-derived TTA1 cell line overexpressed MET. By using FISH and relative quantification by qPCR, it was demonstrated that this overexpression resulted from a amplification with more than 20 copies.