Prolonged activated partial thromboplastin time due to plasma prekallikrein deficiency: a case study and literature review on its clinical significance

Severe Prekallikrein Deficiency Associated with Low Level of Factor XII: A Case Report

Hereditary deficiency of plasma prekallikrein (PPK) is a rare autosomal recessive disease. The affected patients are often asymptomatic and diagnosed incidentally during preoperative investigations or during hospitalization by isolated prolongation of activated partial thromboplastin time (aPTT). In this article, we report, a 46-year-old woman who was candidate for two invasive procedures (thyroid FNA and hysterectomy) and underwent preoperative evaluation. Due to prolonged aPTT with normal PT she was referred to the IBTO reference coagulation laboratory for specific coagulation assays. Ultimately, the examinations revealed severe PPK deficiency (<1%) with partial deficiency of factor XII level (25%).

Resolving Differential Diagnostic Problems in von Willebrand Disease, in Fibrinogen Disorders, in Prekallikrein Deficiency and in Hereditary Hemorrhagic Telangiectasia by Next-Generation Sequencing

Diagnosis of rare bleeding disorders is challenging and there are several differential diagnostics issues. Next-generation sequencing (NGS) is a useful tool to overcome these problems. The aim of this study was to demonstrate the usefulness of molecular genetic investigations by summarizing the diagnostic work on cases with certain bleeding disorders. Here we report only those, in whom NGS was indicated due to uncertainty of diagnosis or if genetic confirmation of initial diagnosis was required. Based on clinical and/or laboratory suspicion of von Willebrand disease (vWD, n = 63), hypo-or dysfibrinogenemia (n = 27), hereditary hemorrhagic telangiectasia (HHT, n = 10) and unexplained activated partial thromboplastin time (APTT) prolongation (n = 1), NGS using Illumina platform was performed. Gene panel covered 14 genes (ACVRL1, ENG, MADH4, GDF2, RASA1, F5, F8, FGA, FGB, FGG, KLKB1, ADAMTS13, GP1BA and VWF) selected on the basis of laboratory results. We identified forty-seven mutations, n = 29 (6 novel) in vWD, n = 4 mutations leading to hemophilia A, n = 10 (2 novel) in fibrinogen disorders, n = 2 novel mutations in HHT phenotype and two mutations (1 novel) leading to prekallikrein deficiency. By reporting well-characterized cases using standardized, advanced laboratory methods we add new pieces of data to the continuously developing “bleeding disorders databases”, which are excellent supports for clinical patient management.