Hemophilia is a disease of genetic origin, recessive and linked to the X chromosome, which contains the genes that code for the hemostatic factors VIII and IX. Some structural or molecular alterations of these genes cause a quantitative or functional deficiency of factor VIII (FVIII) in Hemophilia A, also called “classical hemophilia”, and factor IX (FIX) in Hemophilia B or “Christmas disease“. The disease is inherited in 70% of cases; in the other 30% it is the result of a de novo mutation whose propositus will inherit it from its offspring with the same recessive pattern linked to X. Because hemophilia is linked to this chromosome with a recessive pattern, it manifests clinically only in males ; women are the carriers, although, exceptionally, they suffer under very special conditions.
Why was it known as the disease of kings?
Hemophilia is marked by classic anecdotes in the history of medicine. For example, in the time of Queen Victoria, it was believed that it was a “real” disease, prevalent only in monarchies, since the phenotype was clearly expressed among the royal families (reason that by itself gave more resonance). Today we know that hemophilia has an almost worldwide distribution with cases documented in all races and ethnic groups. The earliest records go back to the Talmud and the Egyptian papyri, which describe cases that, in the light of current knowledge, could be classified as subjects with hemophilia.
What is your clinical picture?
Hemarthrosis, deep muscular hematomas and cerebral hemorrhages constitute 95% of hemophilia hemorrhages, although they can potentially affect any part of the body. The most frequent hemorrhages are, by far, hemarthrosis (in the load joints: knees, ankles and elbows), followed by superficial and deep muscular hematomas. Hemophilia are clinically characterized by a hemorrhagic tendency proportional to the degree of deficiency of the haemostatic factor, although there are usually exceptions. The functional level of the deficient factor allows classification of the disease into: severe (
How is the diagnosis of hemophilia?
The key aspects for the diagnosis are the clinical history, with emphasis on hereditary family history and the inheritance pattern, the semiology of the hemorrhage, the physical examination and the laboratory tests, both scrutiny and confirmatory.
The laboratory in the diagnosis of hemophilia
It is convenient to start with general scrutiny studies: blood count, peripheral blood smear and basic coagulogram: prothrombin time (PT), activated partial thromboplastin time (aPTT), thrombin time (TT) and bleeding time (TH). The test that best reflects the FVIII and FIX is the aPTT. In a typical patient, the aPTT is prolonged and corrects when adding normal plasma to the test; the rest of the tests remain normal. The definitive diagnosis of hemophilia and its classification are made by measuring the functional level of FVIII or FIX for HA or HB, respectively. The majority of patients have
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