Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0002895 (sickle cell disease)
 11,747 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Restriction site polymorphisms are normal inherited variations in DNA that can be readily detected by restriction endonuclease analysis. Currently, 17 such polymorphisms are recognized within a 60 kb (kilobase) stretch of DNA which includes the beta-globin gene complex. Because of their proximity to the beta-globin gene, often these restriction site polymorphisms can be used to predict inheritance of beta-globin variants that produce disease. For example, restriction site polymorphisms can be used for prenatal diagnosis for the large majority of couples at risk of having a child with beta-thalassemia. When each member of such a couple is heterozygous at one or more of these 17 sites, family studies are usually successful in determining which forms of the polymorphism are co-inherited with the beta-thalassemia genes in that particular family. Subsequently, study of fetal DNA isolated from amniocytes obtained by midtrimester amniocentesis or from chorionic villi obtained by first trimester chorion biopsy will reveal which DNA polymorphisms that fetus has inherited. By deductive reasoning one can then predict which beta-globin genes it has co-inherited. Because of the general nature of these polymorphisms, which are related to the beta-globin gene and its variants only because of their proximity on chromosome 11, they are potentially useful in the prenatal diagnosis of any beta-chain hemoglobinopathy. Some hemoglobinopathies (including alpha-thalassemia, sickle cell anemia, and some cases of beta-thalassemia) can be detected directly by DNA analysis. In these cases in utero diagnosis does not need to rely on restriction site polymorphisms, which require preliminary family studies and are not applicable in all at risk pregnancies. Recently, genetic probes, which are necessary for detecting restriction site polymorphisms, have been isolated for sequences of several genes whose protein products are important in blood coagulation. These include probes for all three genes whose polypeptide products combine to form the fibrinogen molecule as well as probes for the prothrombin, Factor IX, Factor VIII, and antithrombin III genes. Defects in these genes are expected to be the causes of afibrinogenemia, prothrombin deficiency, hemophilia B, hemophilia A, and antithrombin III deficiency, respectively. From experience with other genes, it is expected that restriction site polymorphisms within and/or flanking these genes will be found.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Prenatal diagnosis of hemoglobinopathies by DNA analysis. 299 37

Measurements of the coagulation system were carried out in children with sickle cell disease (SCD) in both steady state and on the 1st day of painful crisis and were compared to age- and sex-matched healthy controls. No significant differences were found in prothrombin time, partial thromboplastin time, thrombin time, reptilase time, plasma fibrinogen, antithrombin III, factor VIII:C, ristocetin-cofactor (Ri-Cof) and platelet aggregation responses to ADP, collagen and adrenaline. Abnormal aggregation responses to ristocetin were noted in all patients with SCD when compared to controls. Daily measurements during the first 4 days of painful crisis showed significant elevation of fibrinogen and Ri-Cof and enhancement of aggregation to ADP and adrenaline by the 3rd day of crisis. It was concluded that the changes noted, rather than being primarily responsible for the onset of crisis, can only be secondary changes arising from the aetiological factors of crisis, i.e. stasis and acute-phase proteins.
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PMID:Coagulation changes in sickle cell disease in early childhood. 311 56

Recent studies suggest that increased activity of the coagulation system, measured with sensitive assays for activation markers, may be important in the pathogenesis of vascular occlusion in sickle cell disease (SCD). Since most of these studies were carried out in adult patients and SCD is an inherited disorder with severe morbidity even in childhood, we decided to determine the activity of the coagulation system in children with SCD. In a prospective study markers of thrombin generation as well as coagulation inhibitors were investigated in 16 homozygous SCD patients and 16 age-matched control children. Significantly increased plasma concentrations of the prothrombin fragment F1+2 and of thrombin-antithrombin III (TAT) complexes were found in SCD patients. The levels of protein C activity and total and free protein S were significantly reduced in SCD patients as compared with control values. Plasma AT III levels were not different in the two groups. We conclude that, in children with SCD, evidence of enhanced thrombin generation is present, which may in part be due to reduced levels of the inhibitors proteins C and S. The clinical relevance of this coagulation imbalance has to be demonstrated.
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PMID:Enhanced thrombin generation in children with sickle cell disease. 819 93

It has recently been proved that, in vitro, red blood cells (RBCs) from patients with homozygous beta-thalassemia behave as procoagulant cells. The procoagulant activity of beta-thalassemia RBCs might be the result of an increased exposure of procoagulant phospholipids (i.e. phosphatidylserine) in the outer leaflet of the membrane. In order to test this hypothesis, we compared the catalytic properties of RBCs of patients with beta-thalassemia and homozygous sickle cell disease (SS-RBCs) with that of controls. The catalytic parameters (Km, kcat) of prothrombin activation by factor Xa were determined both in the absence and in the presence of RBCs. The turn-over number (kcat) of the reaction was not modified by normal, SS- or beta-thalassemia RBCs. The Km was lower in the presence of normal RBCs (mean value: 9.1 microM) than in the absence of cells (26 microM). The Km measured in the presence of either SS-RBCs (mean value: 1.6 microM) or beta-thalassemia RBCs (mean value: 1.5 microM) was significantly lower compared to normal RBCs (p < 0.001). No significant difference was observed between SS-RBCs and beta-thalassemia RBCs. Annexin V, a protein with high affinity and specificity for anionic phospholipids, inhibited the procoagulant activity of both SS-RBCs and beta-thalassemia RBCs, in a dose-dependent manner. More than 95% inhibition was achieved at nanomolar concentrations of annexin V. These results indicate that the procoagulant activity of both beta-thalassemia RBCs and SS-RBCs may be fully ascribed to an abnormal exposure of phosphatidylserine at the outer surface of the red cells.
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PMID:Increased procoagulant activity of red blood cells from patients with homozygous sickle cell disease and beta-thalassemia. 888 64

Abnormalities of coagulation and fibrinolysis were studied in a group of 28 children and young adults with homozygous sickle cell disease (SCD), either in the steady state (n = 12) or during painful crisis (n = 16). Coagulation was explored by standard clotting tests and by measurement of prothrombin complex factors, factor VIII (VIII:C) and antithrombin III (ATIII), protein C (PC) and protein S (PS) activities, while fibrinolytic potential was evaluated using D-dimer, tissue plasminogen activator (t-PA) and plasminogen activator inhibitor (PAI-1) assays. In SCD patients, thrombin time (TT) was constantly shortened, both in the steady state (ratio to control 0.83 +/- 0.08, p < 0.0001) and in crisis (0.76 +/- 0.06, p < 0.0001). Mean levels of prothrombin complex were similar in asymptomatic patients to those in controls, but were significantly decreased during sickle cell crisis (p < 0.05 for factor V and p < 0.0001 for factors II, VII and X). Factor VIII:C was significantly increased, both in the steady state (207 +/- 35%, p < 0.0001) and during crisis (208 +/- 34%, p < 0.0001). PS activity was reduced int he steady state (81 +/- 12%, p < 0.01) and further diminished in crisis (68.5 +/- 27.5%, p < 0.001), while D-dimers were significantly elevated during sickle cell crisis (1028 +/- 675 ng/ml, p < 0.001). In all SCD patients, baseline levels of t-PA antigen were comparable to those in controls, whereas concentrations of PAI-1 antigen were significantly increased, either in the steady state (89.7 +/- 26.3 ng/ml, p < 0.0001) or in crisis (75.0 +/- 24.8 ng/ml, p < 0.0001). These results provide evidence for the presence of circulating activated clotting factors in SCD and for an imbalance of the profibrinolytic and antifibrinolytic systems most likely due to increased PAI-1 levels.
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PMID:Abnormalities of coagulation and fibrinolysis in homozygous sickle cell disease. 897 93

Bone marrow necrosis (BMN) is a relatively rare entity and has been associated with a poor prognosis. It is most commonly found in patients with neoplastic disorders, severe infections and sickle cell anemia. An unusual case of antiphospholipid syndrome (APS) with extensive bone marrow necrosis is described in a 27 year old woman. The patient presented with severe pancytopenia, some cognitive impairment resulting from a previous cerebrovascular accident, fever, hypertension, dyspnoea, tachycardia, hepatosplenomegaly, and vaginal bleeding. Her laboratory findings included a strongly positive Coombs' test (anti-IgG and anti-C3d), a prothrombin time of 23 seconds and an activated partial thromboplastin time of 45 seconds. Anticardiolipin antibody tests were positive. Antinuclear and anti-DNA antibodies were negative but the anti-SM test was positive. A bone marrow biopsy specimen was reported as showing extensive necrosis. The patient was treated with steroids, transfusion, and plasma exchange with some clinical improvement but her pancytopenia did not respond and necessitated frequent transfusions. This case lends further support to the association between APS and BMN.
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PMID:Bone marrow necrosis in antiphospholipid syndrome. 915 83

In the present study we examined if, among other mechanisms, the abnormal exposure of phosphatidylserine at the surface of sickle red blood cells (RBCs) contributes to the hypercoagulability which characterizes homozygous sickle cell disease (SCD). The question was addressed by comparison of the procoagulant properties of RBCs from subjects with various phenotypes (SS, SC and AS) that differ in clinical presentation. As previously reported, SS-RBCs accelerated the prothrombin activation by factor Xa, by decreasing the Km of the reaction compared to normal RBCs. SC-RBCs and AS-RBCs also promoted prothrombin activation although their procoagulant properties were milder compared to SS-RBCs. A significant increase of the thrombin-antithrombin complexes was observed in SS subjects. Prothrombin fragment 1+2 (F1+2) was elevated in half of the SS subjects, but the difference with controls did not reach significance. Elevated levels of thrombin-antithrombin complexes were observed in a number of SC (4/11) and AS (3/12) subjects, but the difference with controls was not significant. A significant correlation was observed between the plasma levels of thrombin-antithrombin complexes in the subjects with SS, AS and AA phenotypes, and the procoagulant properties of RBCs. Our results strongly suggest that the procoagulant properties which characterize SS-RBCs also affect SC-RBCs and AS-RBCs, and that exposure of phosphatidylserine by RBCs contributes to the hypercoagulable state observed in SCD.
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PMID:Sickle cell disease: relation between procoagulant activity of red blood cells from different phenotypes and in vivo blood coagulation activation. 937 37

The prevalence of the prothrombin gene variant (allele 20.210 A), factor V Leiden mutation, and homozygosity for transition 677C-->T in the methylenetetrahydrofolate reductase (MTHFR) gene was determined among patients with sickle cell disease (SCD). The group included 73 patients with median age of 32.3 years with a diagnosis of sickle cell anemia in 53 patients, hemoglobinopathy SC in 16 patients, and four with S/beta(0) thalassemia. Vascular complications such as ischemic stroke or deep vein thrombosis were diagnosed in nine patients. Heterozygosity for the prothrombin gene variant or factor V Leiden mutation was identified in four patients. However, only one patient, who developed ischemic stroke, was identified as a carrier of factor V Leiden mutation. None of the patients presented homozygosity for the thermolabile variant of the MTHFR. These data suggest a low clinical impact of inherited hypercoagulability risk factors in developing thrombosis, occlusive stroke, or mortality data among patients with SCD in Brazil.
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PMID:Prothrombin mutant, factor V Leiden, and thermolabile variant of methylenetetrahydrofolate reductase among patients with sickle cell disease in Brazil. 972 76

Vascular occlusion has a central role in the pathophysiology of sickle cell disease (SCD) and, although there is little evidence that thrombosis alone is responsible, patients with sickle cell disease are known to have an ill-defined but increased thrombotic risk. The most serious complication of this in childhood is stroke which occurs in 7-10% of children and a further 14% have asymptomatic cerebrovascular disease (CVD) on imaging. We have performed a comprehensive profile of coagulation inhibitors and markers of thrombin generation in 96 children (83 nontransfused [NTx] and 13 transfused [Tx]) with steady-state SCD and 18 healthy sibling controls. The levels of protein S (free and total) and heparin cofactor II were reduced in both the NTx and Tx groups compared to controls and protein C and APC resistance ratios were reduced in the NTx group only. Antithrombin levels were not different from controls. Thrombin-antithrombin complexes and prothrombin fragment F1+2 were increased in both patient groups. In the NTx subgroups with or without CVD there were no differences for any of the parameters measured except for lower haemoglobin levels and higher white cell counts in those with asymptomatic CVD. We conclude that children with SCD have a reduction in levels of the majority of the coagulation inhibitors and increased thrombin generation in the steady-state and these are only partially reversed by transfusion. However, these abnormalities do not appear to play a primary role in the development of cerebrovascular disease.
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PMID:Prothrombotic changes in children with sickle cell disease: relationships to cerebrovascular disease and transfusion. 988 16

A 27-year-old patient at 13 weeks' gestation maintained on subcutaneous heparinization due to hemoglobin S and hemoglobin C (SC) sickle cell disease and previous splenic vein thrombosis presented with spontaneous acute onset of severe left lower abdominal and groin pain. The pain, which radiated to the anterior aspect of the thigh, was associated with nausea and vomiting and was exacerbated by extension of the left lower extremity. The patient was hemodynamically stable, yet during the first 24 h of hospitalization a marked decrease in hematocrit from 29% to 22% occurred. Contrast computed tomography (CT) revealed an extensive abdominal-pelvic, retroperitoneal hematoma extending approximately 15 cm in length from above L5 cephalad to below the greater trochanter of the left femur caudally. The retroperitoneal hemorrhage self-tamponaded and did not require surgical management. The dosage of heparin was decreased and maintained with appropriate activated partial prothrombin (aPTT) levels. To our knowledge, this is the first report of a spontaneous retroperitoneal hemorrhage complicating heparin anticoagulation in pregnancy. Unusual hemorrhagic complications of anticoagulation therapy are discussed.
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PMID:Extensive spontaneous retroperitoneal hemorrhage: an unusual complication of heparin anticoagulation during pregnancy. 1040 6


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