A paradoxical thrombogenic mutation in factor II at the target site of arthropod bleeding toxin

A fibrinogen-related protein mediates the recognition of various bacteria and haemocyte phagocytosis in oyster Crassostrea gigas

The family of fibrinogen-related proteins (FREPs) is a group of proteins with fibrinogen-like (FBG) domains, which play important roles as pattern recognition receptors (PRRs) in the innate immune responses. In the present study, a fibrinogen-like protein was identified from the oyster Crassostrea gigas (defined as CgFREP1). The open reading frame of CgFREP1 was of 966 bp that encoded a predicted polypeptide of 321 amino acids comprising a signal peptide and a fibrinogen-like domain. The mRNA expression of CgFREP1 was detected in all the examined tissues. The recombinant CgFREP1 (rCgFREP1) displayed binding activities to lipopolysaccharide (LPS), mannose (MAN), as well as Gram-positive bacteria (Micrococcus luteus and Staphylococcus aureus) and Gram-negative bacteria (Vibrio splendidus and Escherichia coli). The rCgFREP1 displayed the agglutinating activity towards M. luteus, V. splendidus and E. coli in the presence of Ca²⁺. rCgFREP1 was able to enhance the phagocytic activity of haemocytes towards V. splendidus, and exhibited binding activity to the CUB domain of CgMASPL-1. These results suggest that CgFREP1 not only serves as a PRR to recognize and agglutinate different bacteria but also mediates the haemocytes phagocytosis towards V. splendidus.

Simultaneous Detection of CNVs and SNVs Improves the Diagnostic Yield of Fetuses with Ultrasound Anomalies and Normal Karyotypes

The routine assessment to determine the genetic etiology for fetal ultrasound anomalies follows a sequential approach, which usually takes about 6–8 weeks turnaround time (TAT). We evaluated the clinical utility of simultaneous detection of copy number variations (CNVs) and single nucleotide variants (SNVs)/small insertion-deletions (indels) in fetuses with a normal karyotype with ultrasound anomalies. We performed CNV detection by chromosomal microarray analysis (CMA) or low pass CNV-sequencing (CNV-seq), and in parallel SNVs/indels detection by trio-based clinical exome sequencing (CES) or whole exome sequencing (WES). Eight-three singleton pregnancies with a normal fetal karyotype were enrolled in this prospective observational study. Pathogenic or likely pathogenic variations were identified in 30 cases (CNVs in 3 cases, SNVs/indels in 27 cases), indicating an overall molecular diagnostic rate of 36.1% (30/83). Two cases had both a CNV of uncertain significance (VOUS) and likely pathogenic SNV, and one case carried both a VOUS CNV and an SNV. We demonstrated that simultaneous analysis of CNVs and SNVs/indels can improve the diagnostic yield of prenatal diagnosis with shortened reporting time, namely, 2–3 weeks. Due to the relatively long TAT for sequential procedure for prenatal genetic diagnosis, as well as recent sequencing technology advancements, it is clinically necessary to consider the simultaneous evaluation of CNVs and SNVs/indels to enhance the diagnostic yield and timely TAT, especially for cases in the late second trimester or third trimester.

A Novel Heterozygous Variant in F2 Gene in a Chinese Patient With Coronary Thrombosis and Acute Myocardial Infarction Leads to Antithrombin Resistance

Thrombophilia refers to a group of conditions where the blood clots more easily than normal. These blood clots can cause problems such as deep vein thrombosis or pulmonary embolism. Most kinds of mutated coagulation factors II (F2) exhibit lower procoagulant activity, but in some cases, a higher coagulation rate has been observed. The underlying mechanism is that those variations can prevent F2s from being inhibited by antithrombin, leading to a contiguous activation of procoagulation, and causing recurrent thromboembolism. In this study, a patient was admitted to our hospital due to repeated chest pain for 2 days and aggravated for 4 h. A medical history investigation showed that he had three deep venous thromboses in the lower limbs and one portal vein thrombosis events during the past 10 years. The electrocardiogram showed Q wave elevation and slight ST segment elevation in lead V2, and coronary angiogram showed a total occlusion of the left anterior descending artery. Laboratory testing found that troponin I was obviously elevated. Family history also indicated that both his father (II-3) and grandfather (I-1) died from pulmonary thromboembolism. Whole-exome sequencing was performed to detect the genetic lesion of the patient, and a novel mutation (c.1621 C>T/p.R541W) of F2 was identified in the patient. This novel mutation resulted in a substitution of arginine by tryptophan, leading to antithrombin resistance (ATR). Our study is consistent with previously published papers. In conclusion, this study not only identifies a novel mutation of F2 and will contribute to the genetic diagnosis and counseling of families with thrombosis but also suggests that the site p.R541 of F2 may play a crucial role in thrombosis.