Congenital fibrinogen disorders include a spectrum of defects that fall into two categories: quantitative (type I) and qualitative (type II) fibrinogen disorders. Quantitative (type I) disorders include the absence of fibrinogen (afibrinogenemia) or low fibrinogen activity and antigen levels typically…
Introduction Inherited deficiencies of factors II, V, and X (FII, FV, and FX) are rare (estimated frequencies are FII, 1 in 2,000,000; FV, 1 in 1,000,000; and FX, 1 in 1,000,000). Patients who are homozygous or compound heterozygous for defects…
Factor VII (FVII) deficiency is the most common autosomal recessive rare bleeding disorder. It was first described in 1951 and has an estimated prevalence of 1 in 500,000. The manifestation of bleeding symptoms in FVII deficiency is clinically heterogeneous. Some…
Factor XI (FXI) deficiency, was first described in 1953. It is characterized by a highly variable bleeding phenotype. Some patients have no apparent excessive bleeding while others have more substantial bleeding. In contrast to other coagulation factor deficiencies, excessive bleeding…
Hemophilia B, also known as Christmas disease, results from a congenital deficiency or absence of coagulation factor IX (FIX). It is an X-linked recessive disorder with an incidence of approximately 1:25,000 live male births and accounts for 15%–20% of hemophilia…
Hemophilia A (also known as classical hemophilia) results from congenital deficiency of factor VIII (FVIII). It is an X-linked recessive disorder that results in decreased or absent circulating FVIII activity, leading to lifelong bleeding tendency. Hemophilia A has an incidence…
von Willebrand disease (VWD) is the most common hereditary bleeding disorder affecting as much as 1% of the general population. The VWF (von Willebrand factor) protein has three essential hemostatic functions: (1) binding to FVIII thereby prolonging its half-life, (2)…
Introduction The antiphospholipid (aPL) syndrome (APS) is an autoimmune thrombophilic condition that is defined by a combination of clinical and laboratory criteria. In general terms, APS patients have developed circulating antibodies against plasma proteins that bind to phospholipids (i.e., aPL…
Thrombotic thrombocytopenic purpura (TTP) is a syndrome consisting of microangiopathic hemolytic anemia (MAHA), thrombocytopenia, and end-organ damage secondary to microvascular thrombi. Anemia, thrombocytopenia, fever, neurological signs, and renal dysfunction makeup the classic pentad; however, TTP can present without the full…
Hemolytic uremic syndrome (HUS) is a thrombotic microangiopathy (TMA) characterized by the triad of microangiopathic hemolytic anemia, thrombocytopenia, and acute kidney injury (AKI). This disease can be divided into three major subtypes: typical HUS, atypical HUS (aHUS), and DEAP-HUS (deficiency…