Combined Mutation And Rearrangement Screening by Quantitative PCR High-Resolution Melting: Is It Relevant for Hereditary Recurrent Fever Genes?

The recent identification of genes implicated in hereditary recurrent fevers has allowed their specific diagnosis. So far however, only punctual mutations have been identified and a significant number of patients remain with no genetic confirmation of their disease after routine molecular approaches such as sequencing. The possible involvement of sequence rearrangements in these patients has only been examined in familial Mediterranean fever and was found to be unlikely. To assess the existence of larger genetic alterations in 3 other concerned genes, MVK (Mevalonate kinase), NLRP3 (Nod like receptor family, pyrin domain containing 3) and TNFRSF1A (TNF receptor superfamily 1A), we adapted the qPCR-HRM method to study possible intragenic deletions and duplications. This single-tube approach, combining both qualitative (mutations) and quantitative (rearrangement) screening, has proven effective in Lynch syndrome diagnosis. Using this approach, we studied 113 unselected (prospective group) and 88 selected (retrospective group) patients and identified no intragenic rearrangements in the 3 genes. Only qualitative alterations were found with a sensitivity similar to that obtained using classical molecular techniques for screening punctual mutations. Our results support that deleterious copy number alterations in MVK, NLRP3 and TNFRSF1A are rare or absent from the mutational spectrum of hereditary recurrent fevers, and demonstrate that a routine combined method such as qPCR-HRM provides no further help in genetic diagnosis. However, quantitative approaches such as qPCR or SQF-PCR did prove to be quick and effective and could still be useful after non contributory punctual mutation screening in the presence of clinically evocative signs

Response to Li and Zhang: Infevers, a human gene mutation database for autoinflammatory diseases including disseminated superficial actinic porokeratosis

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Mevalonate Kinase-Associated Diseases: Hunting for Phenotype–Genotype Correlation

Mevalonate kinase-associated diseases (MKAD) are caused by pathogenic mutations in the mevalonate kinase gene (MVK) and encompass several phenotypically different rare and hereditary autoinflammatory conditions. The most serious is a recessive systemic metabolic disease called mevalonic aciduria, and the most recently recognized is disseminated superficial actinic porokeratosis, a dominant disease limited to the skin. To evaluate a possible correlation between genotypes and (1) the different MKAD clinical subtypes or (2) the occurrence of severe manifestations, data were reviewed for all patients with MVK variants described in the literature (N = 346), as well as those referred to our center (N = 51). The genotypes including p.(Val377Ile) (homozygous or compound heterozygous) were more frequent in mild systemic forms but were also sometimes encountered with severe disease. We confirmed that amyloidosis was more prevalent in patients compound heterozygous for p.(Ile268Thr) and p.(Val377Ile) than in others and revealed new associations. Patients homozygous for p.(Leu264Phe), p.(Ala334Thr) or compound heterozygous for p.(His20Pro) and p.(Ala334Thr) had increased risk of severe neurological or ocular symptoms. All patients homozygous for p.(Leu264Phe) had a cataract. The variants associated with porokeratosis were relatively specific and more frequently caused a frameshift than in patients with other clinical forms (26% vs. 6%). We provide practical recommendations focusing on phenotype–genotype correlation in MKAD that could be helpful for prophylactic management

REPLY: De-Escalation of the P2Y12 Inhibitor After Acute Coronary Syndromes According to On-Treatment Platelet Reactivity A Promising Step of Enormous Magnitude That Should Be Explored

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Potential mechanism of acute stent thrombosis with bivalirudin following percutaneous coronary intervention in acute coronary syndromes

International audienceClinical trials have demonstrated an excess of acute stent thrombosis (AST) in acute coronary syndromes patients (ACS) undergoing percutaneous coronary intervention (PCI) with bivalirudin compared to heparin. We aimed to investigate the potential mechanisms responsible for thrombus formation under bivalirudin.We compared heparin and bivalirudin during PCI for ACS in a prospective monocentre randomized study. Twenty patients were included after coronary angiography and received a loading dose (LD) of 180mg of ticagrelor at the time of PCI. They were randomly assigned to heparin (70UI/kg) intra-venous (IV) bolus or bivalirudin IV bolus of 0.75mg/kg followed by an infusion of 1.75mg/kg/h until the end of the PCI. The VASP index and thrombin generation test were used to assess the course of platelet reactivity (PR) and thrombin generation.Thrombin generation and PR were identical in both groups at baseline. There was no difference in the course of PR following the LD over time. An optimal PR inhibition was reached 4h after the LD of ticagrelor. Heparin and bivalirudin infusion effectively inhibited thrombin generation during PCI. However, 4h after the end of bivalirudin infusion, thrombin generation had returned to its baseline value whereas in the heparin group it remained significantly inhibited compared to baseline and to the bivalirudin group 4h after the end of the infusion (p<0.01 and p<0.02 respectively).The present study suggests that the short half-life of bivalirudin and the quick restoration of thrombin activity at a time when optimal PR is not reached may be responsible for acute stent thrombosis. Clinicaltrial.gov: NCT02428725

Chlorofluoroiodomethane as a potential candidate for parity violation measurements

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