Anti-SERPINC1 monoclonal antibody, clone FQS6482

Antithrombin is a crucial anticoagulant serpin whose even moderate deficiency significantly increases the risk of thrombosis. Most cases with antithrombin deficiency carried genetic defects affecting exons or flanking regions of SERPINC1. We aimed to identify regulatory mutations inSERPINC1 through sequencing the promoter, intron 1 and 2 of this gene in 23 patients with antithrombin deficiency but without known genetic defects. Three cases with moderate antithrombin deficiency (63-78%) carried potential regulatory mutations. One located 200 bp before the initiation ATG and two in intron 1. These mutations disrupted two out of five potential vitamin D receptor elements (VDRE) identified in SERPINC1 with different software. One genetic defect, c.42-1060_-1057dupTTGA, was a new low prevalent polymorphism (MAF: 0.01) with functional consequences on plasma antithrombin levels. The relevance of the vitamin D pathway on the regulation of SERPINC1 was confirmed in a cell model. Incubation of HepG2 with paricalcitol, a vitamin D analog, increased dose-dependently the levels of SERPINC1transcripts and antithrombin released to the conditioned medium. This study shows further evidence of the transcriptional regulation of SERPINC1 by vitamin D and first describes the functional and pathological relevance of mutations affecting VDRE of this gene. Our study opens new perspectives in the search of new genetic defects involved in antithrombin deficiency and the risk of thrombosis as well as in the design of new antithrombotic treatments.

Objectives: In hereditary antithrombin (AT) deficiency it is important to determine the underlying mutation since the future risk of thromboembolism varies considerably between mutations. DNA investigations are in general thought of as flawless and irrevocable, but the diagnostic approach can be critical. We therefore investigated mutation results in the AT gene, SERPINC1, with two different approaches. Design and methods: Sixteen patients referred to the Centre for Thrombosis and Haemostasis, Odense University Hospital, with biochemical indications of AT deficiency, but with a negative denaturing high-performance liquid chromatography (DHPLC) mutation screening (routine approach until recently) were included. As an alternative mutation analysis, direct sequencing of all exons and exon-intron boundaries without pre-selection by DHPLC was performed. Results: Out of sixteen patients with a negative DHPLC mutation screening, discordant results were found in ten patients (62.5%) when using direct sequencing: Eight had the Basel mutation (c.218C>T), while two had the Cambridge II mutation (c.1246G>T). For seven of the ten patients this meant an altered clinical risk-assessment for future thromboses. Conclusions: Awareness must be drawn to the possibility of differences in DNA diagnostics in general and advances when using newer techniques in particular. One should consider re-analysis of results obtained by earlier sequencing strategies, as clinically important information can be overlooked. (C) 2014 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.