Acquired: Anything that is not present at birth but develops some time later. In medicine, the word “acquired” implies “new” or “added.” An acquired condition is “new” in the sense that it is not genetic (inherited) and “added” in the sense that was not present at birth.

Antibody: A type of protein. The body’s immune system produces antibodies when it detects harmful substances, called antigens. Examples of antigens include microorganisms (such as bacteria, fungi, parasites, and viruses) and chemicals.

Anticardiolipin: Antibodies often directed against cardiolipin and found in several diseases including antiphospholipid syndrome.

Anticoagulant: Any agent used to prevent the formation of blood clots.

Antiphospholipid antibody Syndrome: Immune disorder characterized by the presence of abnormal antibodies in the blood associated with abnormal blood clotting, migraine headaches, recurrent pregnancy losses (repeat spontaneous abortions), and low blood platelet counts (thrombocytopenia).

Antithrombin III deficiency: Rare hereditary disorder that generally comes to light when a patient suffers recurrent venous thrombosis and pulmonary embolism. Inheritance is usually autosomal dominant, though a few recessive cases have been noted.

Artery: Vessel that carries blood high in oxygen away from the heart to the body.

Auto-immune disorder: Illness that occurs when the body tissues are attacked by its own immune system.

Budd-Chiari Syndrome: Hepatic vein obstruction is a blockage of the hepatic vein, which carries blood away from the liver.

Candidate Genes: Gene that researchers think may be related to a particular disease or condition based on either its location or function.

Catastrophic Antiphospholipid antibody Syndrome: An accelerated form of the antiphospholipid antibody syndrome (APS) which results in multiorgan failure.

Cerebral Venous Sinus Thrombosis: Rare form of stroke that results from thrombosis (a blood clot) of the dural venous sinuses, which drain blood from the brain. Symptoms may include headache, abnormal vision, any of the symptoms of stroke such as weakness of the face and limbs on one side of the body, and seizures.

Chromosome: an organized structure of DNA and protein that is found in cells. It is a single piece of coiled DNA containing many genes, regulatory elements and other nucleotide sequences.

Coagulation: The clotting of blood. The process by which the blood clots to form solid masses, or clots.

Coagulation Disorders: Disorders that affect the body’s mechanism for blood clotting.

Coagulopathy: Any disorder of blood coagulation.

Cytokine Storm: Potentially fatal immune reaction consisting of a positive feedback loop between cytokines and immune cells, with highly elevated levels of various cytokines.

Deep Vein Thrombosis:A blood clot (thrombus) in a deep vein in the thigh or leg. The clot can break off as an embolus and make its way to the lung, where it can cause respiratory distress and respiratory failure.

Differential Diagnosis: Systematic method used to identify unknowns. This method, essentially a process of elimination, is used by taxonomists to identify living organisms, and by physicians and other qualified healthcare professionals to diagnose the specific disease in a patient.

Disseminated intravascular Coagulation: Also known as consumptive coagulopathy is a pathological activation of coagulation (blood clotting) mechanisms that happens in response to a variety of diseases. As its name suggests, it leads to the formation of small blood clots inside the blood vessels throughout the body.

Embolism: Migrates from one part of the body (through circulation) and causes a blockage (occlusion) of a blood vessel in another part of the body.

Embolus: Abnormal particle (as an air bubble) circulating in the blood.

Exome sequencing: (also known as targeted exome capture) is an efficient strategy to selectively sequence the coding regions of the human genome to identify novel genes associated with rare and common disorders

Factor V Leiden: Genetic disorder of blood coagulation (clotting) that carries an increased risk of venous thromboembolism — the formation of clots in veins that may break loose and travel through the bloodstream to the lungs or brain. Factor V Leiden is the most common inherited disorder of blood clotting in the US, affecting 5% of Caucasians and 1.2% of the Afro-Americans.

Gene: A DNA segment that contributes to phenotype/function. In the absence of demonstrated function a gene may be characterized by sequence, transcription or homology.

Genotype: The genetic constitution (genome) of an individual.

Hemostasis: The stoppage of bleeding or hemorrhage. Also, the stoppage of blood flow through a blood vessel or organ of the body.

Heparin: An anticoagulant (anti-clotting) medication.

Heparin Induced Thrombocytopenia (HIT): The development of thrombocytopenia (low platelet counts) due to the administration of the anticoagulant (blood clotting inhibitor) heparin, either in its “unfractionated” or “low molecular weight” form. It predisposes to thrombosis, the formation of abnormal blood clots inside a blood vessel. If someone receiving heparin develops new or worsening thrombosis, or if the platelet count falls, HIT can be confirmed with specific blood tests.

Hypercoagulable states: Conditions that may lead to the abnormal development of blood clots. Blood clots can develop in either arteries or veins.

Hypercoagulability: The propensity to develop thrombosis (blood clots) due to an abnormality in the system of coagulation.

Hypothesis: Consists either of a suggested explanation for an observable phenomenon or of a reasoned proposal predicting a possible causal correlation among multiple phenomena.

Inherited: Tending to occur among members of a family usually by heredity.

International Normalized Ratio (INR): A system established by the World Health Organization (WHO) and the International Committee on Thrombosis and Hemostasis for reporting the results of blood coagulation (clotting) tests. All results are standardized using the international sensitivity index for the particular thromboplastin reagent and instrument combination utilized to perform the test.

Magnetic Resonance Imaging (MRI): A special radiology technique designed to image internal structures of the body using magnetism, radio waves, and a computer to produce the images of body structures.

Multiple System Failure: Failure of two or more systems in the body as, for example, the cardiovascular and renal systems. Multiple system failure is also known as multiple organ failure, as when both the heart and kidney give out.

Phenotype: The appearance of an individual, which results from the interaction of the person’s genetic makeup and his or her environment.

Protein: A large molecule composed of one or more chains of amino acids in a specific order determined by the base sequence of nucleotides in the DNA coding for the protein. Proteins are required for the structure, function, and regulation of the body’s cells, tissues, and organs. Each protein has unique functions. Proteins are essential components of muscles, skin, bones and the body as a whole. Examples of proteins include whole classes of important molecules, among them enzymes, hormones, and antibodies.

Protein C Deficiency: Protein C is a protein in plasma that enters into the cascade of biochemical events leading to the formation of a clot. Deficiency of protein C results in thrombotic (clotting) disease and excess platelets with recurrent thrombophlebitis (inflammation of the vein that occurs when a clot forms). The clot can break loose and travel through the blood stream (thromboembolism) to the lungs causing a pulmonary embolism, brain causing a stroke (cerebrovascular accident), heart causing an early heart attack, skin causing what in the newborn is called neonatal purpura fulminans, the adrenal gland causing hemorrhage with abdominal pain, abnormally low blood pressure (hypotension), and salt loss. Protein C deficiency is due to possession of one gene (heterozygosity) in chromosome band 2q13-14. The possession of two such genes (homozygosity) is usually lethal.

Protein S Deficiency: Disorder associated with increased risk of venous thrombosis. Protein S, a vitamin K-dependent physiological anticoagulant, acts as a nonenzymatic cofactor to activated protein C in the proteolytic degradation of factor Va and factor VIIIa. Decreased (antigen) levels or impaired function (activity) of protein S, leads to decreased degradation of factor Va and factor VIIIa and an increased propensity to venous thrombosis.

Pulmonary embolism: A blockage of the pulmonary artery or one of its branches, usually occurring when a deep vein thrombus (blood clot from a vein) becomes dislodged from its site of formation and travels, or embolizes, to the arterial blood supply of one of the lungs. This process is termed thromboembolism.

Streptokinase: A protein produced by beta-haemolytic streptococcus and is used as an effective and cheap clot-dissolving medication in some cases of myocardial infarction (heart attack) and pulmonary embolism. It belongs to a group of medications known as fibrinolytics, and works by activating plasminogen through cleavage to produce plasmin.

Thromboembolism: Formation in a blood vessel of a clot (thrombus) that breaks loose and is carried by the blood stream to plug another vessel.

Thrombolytic Agent: A drug that is able to dissolve a clot (thrombus) and reopen an artery or vein.

Thrombosis: Formation or presence of a blood clot within a blood vessel.

Thrombotic Thrombocytopenia Purpura (TTP): Life-threatening disease involving embolism and thrombosis (plugging) of the small blood vessels in the brain. TTP is characterized by platelet microthrombi (tiny traveling clots composed of platelets, the clotting cells in the blood), thrombocytopenia (lack of platelets), hemolytic anemia (from the breakup of red blood cells), fever, renal (kidney) abnormalities and neurologic changes such as neurological signs such as aphasia, blindness, and convulsions.

Thrombus: Clot of blood formed within a blood vessel and remaining attached to its place of origin.

Vein: Blood vessel that carries blood low in oxygen content from the body back to the heart.

Warfarin: Anticoagulant drug (brand names: Coumarin, Panwarfin, Sofarin) taken to prevent the blood from clotting and to treat blood clots and overly thick blood.


•Merriam-Webster Online Dictionary. 2009. Retrieved March 4, 2009
•Wikipedia: The Free Encyclopedia. Retrieved March 9, 2009. From Wikimedia Foundation.
•MedTermsTM Medical Dictionary. 2009. Retrieved March 4, 2009.
•Rare Thrombotic Disease Consortium. 2009. Retrieved March 4, 2009.