Whole F8 gene sequencing identified pathogenic structural variants in the remaining unsolved patients with severe hemophilia A.

Background: No F8 genetic abnormality is detected in approximately 1% to 2% of patients with severe hemophilia A (HA) using conventional genetic approaches. In these patients, deep intronic variation or F8 disrupting genomic rearrangement could be causal.

Objectives: The study aimed to identify the causal variation in families with a history of severe HA for whom genetic investigations failed.

Whole F8 gene sequencing combined with splicing functional analyses led to a substantial increase of the molecular diagnosis yield for non-severe haemophilia A.

Introduction: Conventional genetic investigation fails to identify the F8 causal variant in 2.5%-10% of haemophilia A (HA) patients with non-severe phenotypes. In these cases, F8 deep intronic variants could be causal.

Whole F9 gene sequencing identified deep intronic variations in genetically unresolved hemophilia B patients.

Background: The disease-causative variant remains unidentified in approximately 0.5% to 2% of hemophilia B patients using conventional genetic investigations, and F9 deep intronic variations could be responsible for these phenotypes.

Objectives: This study aimed to characterize deep intronic variants in hemophilia B patients for whom genetic investigations failed.

Comprehensive analysis of F8 large deletions: Characterization of full breakpoint junctions and description of a possible DNA breakage hotspot in intron 6.

Background: Large F8 deletions represent 3-5% of the variations found in severe hemophilia A patients, but only a few deletion breakpoints have been characterized precisely.

Objectives: Resolving at the nucleotide level 24 F8 large deletions to provide new data on the mechanisms involved in these rearrangements.

Methods: Breakpoint junctions of 24 F8 large deletions were characterized using a combination of long-range polymerase chain reaction, whole F8 NGS sequencing, and Sanger sequencing.

The challenge of genetically unresolved haemophilia A patients: Interest of the combination of whole F8 gene sequencing and functional assays.

Background: The causative variant remains unidentified in 2%-5% of haemophilia A (HA) patients despite an exhaustive sequencing of the full F8 coding sequence, splice consensus sequences, 5'/3' untranslated regions and copy number variant (CNV) analysis. Next-generation sequencing (NGS) has provided significant improvements for a complete F8 analysis.

Aim: The aim of this study was to identify and characterize pathogenic non-coding variants in F8 of 15 French and Canadian HA patients genetically unresolved, through the use of NGS, mRNA sequencing and functional confirmation of aberrant splicing.

Reversal of rivaroxaban anticoagulant effect by prothrombin complex concentrates: which dose is sufficient to restore normal thrombin generation?

Rivaroxaban has the most available data to support the use of prothrombin complex concentrates (PCC) as a reversal agent. However, PCC might increase the incidence of thrombotic events by shifting the haemostatic balance towards hypercoagulability. We assessed the in vitro efficacy and safety of three 4-factor PCCs for reversing rivaroxaban anticoagulant effect.

Identification of new F8 deep intronic variations in patients with haemophilia A.

Introduction: With current molecular diagnosis, about 1 to 5% of haemophilia A (HA) patients remain genetically unresolved. In these cases, deep intronic variation or structural variation disrupting the F8 gene could be causal.

Aim: To identify the causal variation in four genetically unresolved mild-to-severe HA patients using an F8 mRNA analysis approach.

The highly prevalent deletions in F8 intron 13 found in French mild hemophilia A patients result from both founder effect and recurrent de novo events.

Background: Recently, our group has reported a 13-bp deletion in a poly(T)-track in the F8 intron 13 as the causative variant in approximately 6% of all cases of mild haemophilia A (HA) in France. The systematic screening of mild HA patients for this deletion identified individuals carrying deletions from 9 to 14-bp in the same region.

Aims: To demonstrate that these highly prevalent deletions could result from a recurrent molecular mechanism and to determine the clinical significance of deletions other than 13-bp in size.

Severe hemophilia A caused by an unbalanced chromosomal rearrangement identified using nanopore sequencing.

Unlabelled: Essentials No F8 genetic abnormality is detected in about 2% of severe hemophilia A patients. Detection of F8 structural variants remains a challenge. We identified a new F8 rearrangement in a severe hemophilia A patient using nanopore sequencing.

Splicing analysis of 26 F8 nucleotide variations using a minigene assay.

Background: Classically, the study of splicing impact of variation located near the splice site is performed by both in silico and mRNA analysis. However, RNA sample was rarely available.

Objective: To characterize a panel of putative haemophilia A splicing variations.

Reccurrent F8 Intronic Deletion Found in Mild Hemophilia A Causes Alu Exonization.

Incorporation of distant intronic sequences in mature mRNA is an underappreciated cause of genetic disease. Several disease-causing pseudoexons have been found to contain repetitive elements such as Alu elements. This study describes an original pathological mechanism by which a small intronic deletion leads to Alu exonization.

Why patients with THBD c.1611C>A (p.Cys537X) nonsense mutation have high levels of soluble thrombomodulin?

Background: Recently our group has described a new autosomal dominant bleeding disorder characterized by very high plasma levels of soluble thrombomodulin (TM). The THBD c.1611C>A (p.