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)

Seven patients had sickle cell trait (hemoglobin AS) and vasoproliferative retinopathy. The retinal abnormalities in these seven patients were indistinguishable from those seen in patients with clinically significant sickling hemoglobinopathies (sickle cell-hemoglobin C disease, hemoglobin S-thalassemia disease, and sickle cell anemia). All seven patients also had some evidence of associated systemic disease such as diabetes, syphilis, tuberculosis, or sarcoidosis. In the presence of an associated systemic disease, marked retinopathy can occur in the ordinarily benign condition of sickle cell trait.
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PMID:Proliferative retinopathy in sickle cell trait. Report of seven cases. 84 50

Of 45 patients with proliferative sickle retinopathy in stages III, IV, and V, nine patients (eight with hemoglobin SC disease, one with sickle cell thalassemia) showed spontaneous regression (autoinfarction) of retinal sea fans. One mechanism involved in autoinfarction of neovascular tissue is progressive, centripetal retraction of the anterior vascular arcade of the peripheral retina. In addition, vitreous traction on feeder vessels may result in sluggish blood flow and occlusion of these vessels, or may tear the sea fan completely away from its feeder vessels. In view of the many incidences of vitreous hemorrhages that occur in patients with proliferative retinopathy, however, we recommend treatment of neovascularization rather than prolonged observation.
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PMID:Spontaneous regression (autoinfarction) of proliferative sickle retinopathy. 119 Feb 80

The variable levels of HbF in sickle cell anemia reflect the heterogeneous genetic mix of the beta s-gene-cluster haplotypes and coinheritance of alpha-thalassemia-2 in American SS patients. Clinical severity is less when the level of HbF reaches 20% or 1.2 g/dl or more. The coinheritance of alpha-thalassemia-2 not only increases the intracellular red cell water but modifies the HbF level in accordance with the beta-cluster haplotype. In general, the SS patient with at least one Senegalese haplotype who does not have a CAR haplotype in trans, has a significantly greater probability of maintaining HbF above 20%. This is in part related to the genetic control of the G gamma HbF locus. Such a patient is protected from arteriolar vasculopathy and subsequent major organ destruction. Much of this but perhaps not all of the better health of patients with a Senegalese haplotype can be attributed to the elevation of G gamma HbF. The coinheritance of alpha-thalassemia-2 further decreases the risk of major morbidity of the soft tissues but increases the risk of avascular necrosis of the bony skeleton. Although these heterozygous Senegal patients are healthier, eventually most, in time, will show the deleterious effect of HbS as retinopathy and avascular necrosis usually beginning after age 30 and sickle nephropathy after age 40. Because of the age-specific effect, the onset of the sickle vasculopathy is delayed by nearly 20 years in the Sen/Ben patient with increased G gamma HbF as compared to those with a CAR haplotype or the homozygous Benin. Lifetime elevation of HbF above 20% modifies the severity of disease expression and provides relative protection to the patient with sickle cell anemia.
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PMID:The influence of fetal hemoglobin on the clinical expression of sickle cell anemia. 247 64

In HbSC disease, as in sickle cell anaemia, there is a spectrum of clinical severity. A reduced mean corpuscular volume and haemoglobin concentration, traits typical of thalassaemia, might retard sickling. We therefore ascertained the prevalence of alpha-thalassaemia in 53 adults with HbSC disease and related alpha-globin gene deletion to the haematologic and clinical findings. Alpha-globin genotype was identified by restriction endonuclease gene mapping. Indirect ophthalmoscopy and fluorescein angiography were used to document the presence of proliferative retinopathy. Bone necrosis and infarction were determined roentgenographically or by radionuclide scanning. Either heterozygous or homozygous alpha-thalassaemia-2 was present in 26% of patients. There was no relationship between alpha-globin genotype and haematocrit, pain crises, bone lesions, proliferation retinopathy or clinical severity score.
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PMID:The effects of alpha-thalassaemia in HbSC disease. 663 90

The hemoglobin of 70 diabetics with retinopathy was analysed. 56 patients had pathologically elevated values, 12 values were within the upper normal limit and in 2 cases the findings were normal. This hemoglobin variant is characterized by an increased affinity of oxygen. Clinically and pathologically speaking the elevated HbA1c value could be a causal factor in diabetic retinopathy. Comparisons with sickle cell anemia and thalassemia seem to indicate that hemoglobinopathy and retinopathy are pathogenetically related.
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PMID:[Significance of elevated hemoglobulin A1c for the pathogenesis of diabetic retinopathy]. 686 53

Homozygous alpha+ thalassaemia (alpha-/alpha-) ameliorates some of the clinical manifestations of homozygous sickle cell (SS) disease but its effect on retinal complications remains unknown. This has been assessed by visual examination and fluorescein angiography in 39 subjects with SS disease and homozygous alpha+ thalassaemia and in 39 age/sex matched controls with SS disease but with a normal alpha globin genotype (alpha alpha/alpha alpha). The results indicate that homozygous alpha+ thalassaemia reduces the extent of peripheral retinal vessel closure but has no apparent effect on the frequency of proliferative sickle retinopathy.
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PMID:Influence of alpha thalassaemia on the retinopathy of homozygous sickle cell disease. 843 25

High total haemoglobin levels in homozygous sickle cell (SS) disease are a risk factor for painful crises, avascular necrosis of the femoral head, proliferative sickle retinopathy, and the acute chest syndrome. Since lowering the haemoglobin level may ameliorate these features, understanding the determinants of total haemoglobin may be of practical importance. A range of possible determinants including red cell characteristics, reticulocytes, serum iron, transferrin saturation, serum ferritin, alpha thalassaemia status, red cell mass and plasma volume, oxygen affinity, red cell survival, transferrin receptor and erythropoietin levels have been measured in 62 patients selected to provide a range of total haemoglobin and fetal haemoglobin levels. There were weak negative associations of haemoglobin with mean cell volume and mean cell haemoglobin concentration, strong negative associations with proportional reticulocyte counts, oxygen affinity, plasma volume, serum transferrin receptors, and erythropoietin levels and strong positive associations with red cell mass. Weighted analysis suggested that the statistically independent determinants of haemoglobin level were alpha thalassaemia, sex, red cell mass/body weight, plasma volume/body weight, fetal haemoglobin, and red cell count. The apparent contributions of red cell survival, P50, reticulocyte count, serum transferrin receptor and erythropoietin levels were explained by the effects of these other variables. The independent determinants as a group explained 91% of the variation in haemoglobin level.
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PMID:Determinants of haemoglobin level in steady-state homozygous sickle cell disease. 856 87

Thirteen patients with sickle cell anemia (SS) were found to have two alpha gene deletions with a presumptive genotype of beta(S)/beta(S); -alpha/-alpha. Hematological data showed that this group of patients had elevated Hb A2 level. In order to determine whether the elevation of Hb A2 is typical of SS with a two alpha gene deletion or is due to undiagnosed S-beta(O)-thalassemia with a two alpha gene deletion we looked for the presence or absence of beta(O)-thalassemia by molecular techniques. The latter included reverse dot-blot hybridization to rule out a beta-thalassemia mutation, digestion with CvnI endonuclease followed by Southern blotting and hybridization with a beta genomic probe, and, in selected patients, determination of the synthetic alpha/beta ratio. One of the 13 patients had S-beta(O)-thalassemia with a G-->A mutation at IVS-II-1 indicating that her genotype was beta(S)/beta(O) thalassemia; -alpha/-alpha. The remaining 12 patients were homozygous for the sickle gene, had relatively elevated Hb levels, increased Hb A2 values, and Hb F levels similar to those in patients with SS and four or three alpha genes. At the clinical level, the 12 patients with SS and a two alpha gene deletion had increased prevalence of avascular necrosis, retinopathy, and splenomegaly, but decreased prevalence of leg ulcers and cerebrovascular accidents. Together, the data indicate that SS with a two alpha gene deletion (beta(S)/beta(S); -alpha/-alpha) is a unique subset of patients with SS characterised by distinct hematological and clinical features.
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PMID:Is Hb A2 elevated in adults with sickle-alpha-thalassemia (beta(S)/beta(S); -alpha/-alpha)? 932 76

Thalassaemic patients with diabetes mellitus are at risk of developing retinopathy. To evaluate the prevalence and the characteristics of diabetic retinopathy in thalassaemics we examined 46 patients with beta-thalassaemia major and insulin-dependent diabetes by fluorescein angiography. The study group was matched for sex, age and diabetes duration with a control group of 46 type 1 diabetic patients. Diabetic retinopathy was detected in 26% (12/46) of thalassaemics and in 50% (23/46) of the controls. In thalassaemics the diabetic retinopathy was significantly less severe than in controls (P < 0.0001). The influence of risk factors for diabetic retinopathy (duration of diabetes and metabolic control) was confirmed in the control group. In thalassaemic patients we found no significant correlation between these risk variables and the presence of diabetic retinopathy. Various factors may protect thalassaemics from diabetic retinopathy: heterogeneity of pancreatic functions; high incidence of hypogonadism; contemporary dysfunction of GH and/or glucagon secretion.
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PMID:Prevalence of retinopathy in diabetic thalassaemic patients. 1009 Nov 61

Erythrocytes from diabetic patients exhibit impaired viscoelastic properties when estimated by various methods. We determined erythrocyte filterability through 5-microm pores, in 51 patients with non-insulin-dependent diabetes mellitus, 18 healthy controls, 15 patients with homozygous beta-thalassemia and 15 with beta-thalassemia traits. The filtration measurements were made with a Hemorheometer, which uses the "initial flow rate" principle. To determine the Index of Rigidity (IR) of the red blood cells, we measured the passage time of white blood cell-free erythrocyte suspensions, 8% per volume, through the filter. Diabetic patients had significantly increased IR in comparison to healthy controls and to patients with beta-thalassemia trait, but not at the level found in patients with homozygous beta-thalassemia. In diabetic patients, a strong correlation between IR and the percentage of glycosylated haemoglobin was found (r=0.737, P < 0.0001), and a weaker one with serum unconjugated bilirubin (r=0.363, P=0.0097) and serum total lipids (r=0.321, P=0.0286). Patients with severe retinopathy also had significantly increased IR, in comparison to those with or without mild retinopathy. Anaemic diabetic patients, especially those with the anaemia of chronic disease, also had significantly increased IR in comparison to non-anaemic diabetics. No correlation between IR, MCV, MCH, MCHC, RDW, RBC morphology, serum LDH or the presence of erythrocyte inclusions after incubation with nitrous sodium solution was found. Our findings suggest that glycosylation of skeletal proteins probably contributes significantly to the increased membrane rigidity of diabetic erythrocytes.
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PMID:Impairment of erythrocyte viscoelasticity is correlated with levels of glycosylated haemoglobin in diabetic patients. 1148 49


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