Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0039730 (thalassemia)
 10,305 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The adherence of red blood cells (RBC) to endothelial cells (EC), shown to correlate with microvascular occlusion in sickle cell disease and malaria, is considered a major contributor to microcirculatory disorders. In the present study the adherence to EC was markedly enhanced with RBC from beta-thalassaemia major (TM) patients, and even more so with RBC from beta-thalassaemia intermedia (TI) patients (10-fold and 25-fold higher than normal, respectively). It is proposed that enhanced RBC/EC adherence may contribute to the microcirculatory disorders observed in thalassaemia, especially in TI patients who are particularly known to suffer from leg ulcers.
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PMID:Enhanced adherence of beta-thalassaemic erythrocytes to endothelial cells. 1044 84

The use of hydroxyurea for the prevention of sickle cell crises in patients with homozygous HbS disease is now well established. The beneficial effects of this compound stem from (a) selective enrichment of red cells containing an increased amount of fetal hemoglobin, which inhibits HbS polymerization, and (b) a decrease of leukocytes, platelets, and reticulocytes, which significantly limits their adherence to the vascular wall. We report the results of a clinical trial of hydroxyurea on 55 Greek-origin patients with sickle cell/beta-thalassemia and 14 patients with homozygous HbS disease who have been treated with hydroxyurea for several years. Such patients have a higher probability to benefit from hydroxyurea therapy, since in addition to its antisickling effect, the increase of gamma-chain synthesis is expected to diminish the deleterious effects of the unbound alpha-globin chains. Selection of patients and monitoring throughout the whole trial were done by the same clinicians. Quantitative expression of the clinical condition was done using a system scoring several outcome parameters. For a period of 52 months prior to starting treatment, the total score of severity for 59 evaluable patients was 1182 points (3068 patient-weeks), while for the 12,018 patient-weeks of the trial this parameter fell to only 82 points. Other observations of interest include the significant improvement of a group of patients with hepatic cholestasis, the development of leg ulcers possibly related to the treatment, and the dramatic increase of hemoglobin F, often in association with an increase of the total hemoglobin levels as a result of decreased hemolysis.
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PMID:Reduction of the clinical severity of sickle cell/beta-thalassemia with hydroxyurea: the experience of a single center in Greece. 1111 83

Hydroxyurea is commonly used in the treatment of various myeloproliferative disorders. In conventional pediatric clinical practice, its use is limited to benign hematologic conditions such as sickle cell disease and thalassemia. Long-term hydroxyurea use is associated with various adverse mucocutaneous effects including hyperpigmentation, alopecia, leg ulcers, and lichenoid eruptions. We report a 10-year-old boy with chronic myelogenous leukemia who presented with hyperpigmentation of the skin and nails 3 months after the start of hydroxyurea therapy. Melanonychia of all 20 nails with involvement of all three mucocutaneous areas (skin, nails, and mucosa) at presentation was a unique feature in our patient. With the recently increasing pediatric use of hydroxyurea in a variety of disorders, its benign and not so uncommon cutaneous adverse effects are emphasized here.
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PMID:Cutaneous manifestations of hydroxyurea therapy in childhood: case report and review. 1507 51

The distribution of clinical features was examined in subjects with homozygous sickle cell (SS) disease in the Jamaican Cohort Study to determine whether there is evidence of distinct clustering of symptoms or clinical phenotypes. A twofold model yielded groups that could be interpreted as painful crisis or leg ulcer phenotypes and 78% of patients were classified with 95% confidence into one of these. The painful crisis phenotype also manifested higher frequencies of dactylitis, meningitis/septicaemia, acute chest syndrome and stroke. Attempts to define a three-group model were less convincing although 43% of patients could be allocated with 95% confidence. The three-group model essentially divided subjects with the leg ulcer phenotype into subgroups with higher and lower frequencies of painful crisis, dactylitis, meningitis/septicaemia and acute chest syndrome. In the three-group model, the painful crisis phenotype had lower total haemoglobin, fetal haemoglobin, mean cell volume and higher reticulocytes but there was no apparent influence of alpha thalassaemia or beta globin haplotype. Both environmental and genetic factors are likely to contribute to most manifestations of SS disease and the evidence for different clinical phenotypes suggests that a search for associated genetic polymorphisms may provide insights into the mechanisms of clinical variability in SS disease.
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PMID:Are there clinical phenotypes of homozygous sickle cell disease? 1528 56

Although the cutaneous effects of hydroxyurea have been described for patients with sickle cell anemia, myeloproliferative disorders, and psoriasis, there are no reports of cutaneous adverse effects from hydroxyurea when used for patients with intermediate thalassemia. Therefore 43 patients with intermediate thalassemia treated with hydroxyurea were examined by a dermatologist, and pertinent cutaneous findings were recorded. These patients had received hydroxyurea for a mean of 15.5 months. Nineteen had cutaneous hyperpigmentation, eight had xerosis, and three were found to have one cafe au lait macule each. Eleven patients had nail abnormalities, including nail ridging, partial leukonychia, and longitudinal melanonychia. There were no cases of leg ulceration. It was concluded that the risk of developing leg ulcers and pigmentary disorders appears to be related to the underlying disease being treated, as well as to a patient's age, gender, and pigmentation.
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PMID:Cutaneous adverse reactions to hydroxyurea in patients with intermediate thalassemia. 1557 45

We report a preliminary clinical experience in the use of hydroxyurea (HU) for the treatment of leg ulcers in thalassaemia intermedia patients with associated endocrine complications. We administered HU 1 g/day to 6 adult patients with thalassaemia intermedia for 90 days. We observed an improvement (3 patients) or healing (3 patients) of chronic leg ulcers. Recurrence was observed in the absence of maintenance therapy (2 patients). Two patients discontinued HU because of adverse effects (stomach pain and fever). No significant increase in total Hb or HbF levels occurred. In conclusion, HU appears suitable for the treatment of leg ulcers unresponsive to conventional treatment in patients with thalassaemia intermedia.
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PMID:Healing of leg ulcers with hydroxyurea in thalassaemia intermedia patients with associated endocrine complications. 1646 21

Cutaneous leg ulcers are common in sickle cell anaemia and their risk might be genetically determined. Sickle cell anaemia patients were studied to examine the relationship of leg ulcers with haemolysis and with single nucleotide polymorphisms (SNPs) in candidate genes that could affect sickle vasoocclusion. Leg ulcer patients had lower haemoglobin levels and higher levels of lactate dehydrogenase, bilirubin, aspartate transaminase and reticulocytes than did control patients with sickle cell anaemia but without leg ulcers. Age-adjusted comparisons showed that sickle cell anaemia-alpha thalassaemia was more frequent among controls than cases. These results strongly suggested that the likelihood of having leg ulcers was related to the intensity of haemolysis. 215 SNPs in more than 100 candidate genes were studied. Associations were found with SNPs in Klotho, TEK and several genes in the TGF-beta/BMP signalling pathway by genotypic association analyses. KL directly or indirectly promotes endothelial nitric oxide (NO) production and the TEK receptor tyrosine kinase is involved in angiogenesis. The TGF-beta/BMP signalling pathway modulates wound healing and angiogenesis, among its other functions. Haemolysis-driven phenotypes, such as leg ulcers, could be improved by agents that reduce sickle erythrocyte density or increase NO bioavailability.
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PMID:Sickle cell leg ulcers: associations with haemolysis and SNPs in Klotho, TEK and genes of the TGF-beta/BMP pathway. 1668 47

Thalassemia intermedia encompasses a wide clinical spectrum of beta-thalassemia phenotypes. Some thalassemia intermedia patients are asymptomatic until adult life, whereas others are symptomatic from as young as 2 years of age. A number of clinical complications commonly associated with thalassemia intermedia are rarely seen in thalassemia major, including extramedullary hematopoiesis, leg ulcers, gallstones and thrombophilia. Prevention of these complications, possibly with blood transfusion therapy, is ideal since they may be difficult to manage. Currently, many patients with thalassemia intermedia receive only occasional or no transfusions, since they are able to maintain hemoglobin levels between 7-9 g/dl; the risk of iron overload, necessitating adequate chelation therapy, is also a contributing factor. At present, there are no clear guidelines for initiating and maintaining transfusions in thalassemia intermedia for the prevention or treatment of complications. Here, we review the major clinical complications in thalassemia intermedia and suggest some therapeutic strategies based on retrospective clinical observations.
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PMID:Thalassemia intermedia: revisited. 1673 33

Screening for pulmonary hypertension (pHTN) has not yet become routine in sickle cell disease (SCD), despite clinical evidence of its high prevalence and associated mortality. Our objectives are to identify clinical conditions and laboratory findings predictive of/or associated with pHTN. One hundred twenty-five adult outpatients with Hb SS, SC, SOArab, Sbeta(0), or Sbeta(+) thalassemia, who underwent echocardiography and/or right heart catheterization due to cardiorespiratory symptoms, were studied. pHTN was identified in 36% (28/77) of SS/Sbeta(0) and in 25% (12/48) of SC/SOArab/Sbeta(+) patients studied. In SS/Sbeta(0) patients, pHTN was associated with low hemoglobin, low GFR, increasing age, no history of treatment with hydroxyurea and a history of leg ulcers, with trends for associations with higher total bilirubin, LDH levels, systolic systemic blood pressure, history of avascular necrosis, seizures, and cerebrovascular events. Twelve (40%) of the SS/Sbeta(0) patients with pHTN had >or= 1+ proteinuria. (P<0.039). The presence of proteinuria correlated with lower GFR and had a high positive predictive value (0.60) for pHTN in subjects with SS/Sbeta(0). The data also provided evidence that pHTN in this population is associated with right heart failure, with echocardiographic evidence of right ventricle enlargement and pericardial effusion. This study confirmed that even relatively mild elevations in pulmonary pressure are associated with high prospective mortality (hazard ratio: 15.9). We concluded that pHTN has a high prevalence in all Hb S related syndromes and is associated with increased mortality in SS/Sbeta(0). Kidney dysfunction, as indicated by proteinuria or decreased GFR, also represents sufficient reason to screen for pHTN.
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PMID:Pulmonary hypertension associated with sickle cell disease: clinical and laboratory endpoints and disease outcomes. 1772 99

Sickle cell disease (SCD), the commonest single gene disorder worldwide, is an inherited disease that has different clinical and hematological manifestations in different populations. The objective of this study is to describe the characteristics of the Lebanese SCD population. This was a retrospective study that included information on 387 patients with either sickle cell anemia (SS) or sickle beta-thalassemia (ST). The mean (+/-SD) age was 17.9 years (+/-12.5), and the mean (+/-SD) follow-up was 9.3 +/- 6.9 years. Fifty percent of the patients were males and SS/ST distribution was 3 : 1. The disease was clustered in two geographic areas in North and South Lebanon. Nearly, all patients were Muslims and 56% were the offspring of consanguineous parents. The prevalence of splenomegaly beyond 6 years of age among SS patients was 28.9%. The prevalence rates of stroke, leg ulcers and priapism were 4.1%, 1.4%, and 0.8%, respectively. Comparing the SS and the ST patients, there were no statistically significant differences in the prevalence of all clinical manifestations except for splenomegaly (SS: 28.9%, ST: 54.9%, P-value < 0.001) and splenectomy (SS: 16.1%, ST: 35.7%, P-value < 0.001). In contrast to Northern American populations and similar to some Mediterranean populations, Lebanese SCD patients have a higher prevalence of persistent splenomegaly. The relatively low incidence of thrombotic complications deserves further investigation. The study's limitations include those of any other retrospective study and the fact that not all Lebanese centers caring for inherited hemoglobin disorders were included. However, the results of this first large scale national survey indicate that preventive efforts should target the Northern and Southern regions of Lebanon to decrease the number of new off springs afflicted with this disease similar to what has been successfully achieved with Thalassemia, another hemoglobinopathy that is highly prevalent in the country.
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PMID:Sickle cell disease: the Lebanese experience. 1798 93


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