Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0019045 (hemoglobinopathies)
 2,704 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Anemia is a frequent complication of chronic kidney disease (CKD). Inadequate production of erythropoietin by the failing kidneys leads to decreased stimulation of the bone marrow to produce red blood cells (RBCs). Anemia of CKD develops early and worsens with progressive renal insufficiency. Although over 40% of patients with CKD are anemic, anemia in this population is under-recognized and undertreated. Of considerable importance, anemia is a risk factor for cardiovascular disease and is associated with higher rates of hospitalization and mortality. Despite the availability of erythropoiesis-stimulating proteins (ESPs) to stimulate RBC production in CKD patients, approximately three fourths of patients initiating dialysis have a hemoglobin <11 g/dL. The recognition of anemia of CKD begins with an estimation of glomerular filtration rate (GFR), which can be far lower than a normal serum creatinine might suggest, especially in the elderly and in those with poor nutrition and muscle mass. If GFR is <60 mL/min/1.73 m(2), hemoglobin should be checked. The anemia is diagnosed when the hemoglobin is <12 g/dL in a man or a postmenopausal woman, or <11 g/dL in a premenopausal woman. The cause of anemia should be investigated in these individuals; this can range from erythropoietin deficiency due to CKD, to deficiency of vitamin B(12) and/or folate, iron deficiency, blood loss, inflammation, malignancy, and aluminum intoxication. After other causes of anemia have been excluded, CKD is the most likely etiology, and it should be treated with an ESP. Currently, epoetin alfa and darbepoetin alfa are the only 2 ESPs approved for use in the United States. Extended dosing of ESP has potential advantages for the patient and may also improve resource utilization. Consequently, both agents have been tested for dosing at extended intervals. Adequate iron stores--defined as transferrin saturation >20% and ferritin >100 mg--as well as ESP administration are needed to produce an appropriate increase in hemoglobin. Poor response to treatment with ESP can be due to many factors, including presence of iron deficiency, inflammation, continued blood loss, and hemoglobinopathy.
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PMID:Practical approach to the diagnosis and treatment of anemia associated with CKD in elderly. 1709 34

Recombinant human erythropoietin (rHuEPO) has transformed the management chronic renal failure (CKD) and considerably improved the outcome of patients on regular chronic dialysis. However, a significant number of patients fail to respond to high of Erythropoiesis-stimulating agents (ESAs) and several causes of inadequate response to epoetin therapy have been identified. Some factors, such as gender, age, length of time on dialysis, type of dialysis and co-morbidities such as hemoglobinopathy, are not susceptible to clinical intervention. However, many other factors can be adjusted. Iron deficiency, whether functional or absolute, is the most common factor that limits the response to rHuEPO. Monitoring of iron parameters and a large use of iron supplementation result in an efficient epoetin response. Infection and inflammation have been shown to reduce responsiveness to ESAs by disrupting iron metabolism and increasing the release of pro-inflammatory cytokines that inhibit erythropoiesis. Increase dialysis dose is associated with improvements in anemia correction and reduced requirements for ESAs. Severe hyperparathyroidism and aluminum overload lead to a reduced number of responsive erythroid progenitor cells. Finally, a number of nutritional factors, such as deficiencies of carnitine, vitamin B12, folic acid, and vitamin C, are susceptible to alter erythropoiesis. Optimizing patient response to ESAs therefore requires consideration of many of well-established factors and is important for both patient outcomes and cost of treatment.
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PMID:[Factors affecting the response to erythropoiesis-stimulating agents]. 1737 70

The aim of the study was to investigate whether the well-known high anemia prevalence in pregnant women from the eastern Mediterranean and Asian regions decreased when the women immigrated to a low-frequency region (Denmark). During 70 months, 1,741 pregnant immigrant women referred from primary care to an obligatory hemoglobinopathy screening were eligible for the study, as their screening was negative. To compare this group with a cohort of 205 pregnant ethnic Danish women, the groups were matched by gestational age, and a total of 406 immigrant women were included. Hemoglobin (Hb) and iron status parameters were examined in the two groups. The prevalence of anemia was higher in the immigrant group (20.0%) compared to the Danish women (4.9%) (P < 0.0001). Blood Hb concentration was 119 +/- 12 g/l (mean +/- SD) in the immigrant group compared to 122 +/- 9 g/l in the Danish group (P = 0.01). Erythrocyte mean corpuscular volume (MCV) was also lower in the immigrant group (87 +/- 7 fl vs 96 +/- 4 fl) (P < 0.0001). A total of 13.1% of the immigrant women had an MCV <80 fl (the lower reference limit) compared to 0.0% in the Danish group, and plasma iron, ferritin, and transferrin saturation values indicated iron deficiency. Conclusively, the pregnant immigrant women had significantly higher prevalence of anemia compared to pregnant women of Danish origin. It indicates the need for an alternative routine screening procedure for this population group, which should also include nutritional counselling.
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PMID:Higher prevalence of anemia among pregnant immigrant women compared to pregnant ethnic Danish women. 1803 72

A 52-year-old Dutch male was referred to our laboratory for hemoglobinopathy analysis because of persistent microcytic hypochromic parameters and moderate erythrocytosis in the absence of iron deficiency. The hemoglobin (Hb) pattern was normal and breakpoint polymerase chain reaction (PCR) excluded the six common deletion defects of the alpha gene cluster. Direct sequencing revealed a GCT-->TCT transversion at codon 21 of the alpha2 gene generating an Ala-->Ser single amino acid substitution. The hematological parameters observed in the presence of this mutation are consistent with a compensated heterozygous alpha(+)-thalassemia (thal). However, the neutral mutation and the external position of the residue do not explain an association with this phenotype. Nevertheless, we cannot exclude that the mutation could induce the observed hematological abnormalities and could eventually be considered as a mutation associated with a mild alpha-thalassemic phenotype.
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PMID:Hb Zoetermeer: a new mutation on the alpha2 gene inducing an Ala-->Ser substitution at codon 21 is possibly associated with a mild thalassemic phenotype. 1765 69

Here, we report a rare coincidence of heterozygous hemoglobinopathy (Hb) Stanleyville II and severe pernicious anemia due to autoimmune gastritis. Hb Stanleyville II is characterized by a single base exchange (AAC-->AAA) resulting in a substitution Asn --> Lys at position 78 of hemoglobin alpha2-chain. Under normal conditions this hemoglobinopathy does not cause any symptoms even if present as homozygous variant. However, in our case diagnosis of pernicious anemia was hampered by the absence of typical erythrocytic macrocytosis and hyperchromasia. In addition, interpretation of bone marrow smears was difficult as characteristic findings for pernicious anemia were little pronounced. All known reasons for the absence of typical cytomorphologic signs in pernicious anemia as underlying iron deficiency and thalassemia could be excluded.
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PMID:Cytomorphologic signs of severe pernicious anemia obscured in a patient with heterozygous hemoglobin Stanleyville II. 1768 Aug 15

Recent evidence from a large, randomized, controlled trial has suggested that the universal administration of iron to children in malaria-endemic areas is associated with an increase in adverse health outcomes. The purpose of this paper is to summarize the available ecologic and intervention trials related to iron and malaria in children, and to set these against current knowledge of the biology of host-pathogen interactions involving iron metabolism. We conclude that, although not fully consistent, the balance of evidence confirms that administration of iron (usually in combination with folic acid) increases the incidence of malaria when given without prophylaxis and in the absence of universal access to treatment. The mechanisms by which additional iron can benefit the parasite are far from clear. There is evidence to suggest that the apparent detrimental effect of iron supplementation may vary according to levels of antecedent iron status, the presence of hemoglobinopathies and glucose-6-phosphate dehydrogenase (G6PD) deficiency, and other host genetic variants, such as variants in haptoglobin. The effects of malaria on host iron metabolism are also reviewed and reveal that the key cause of malaria-induced anemia is a maldistribution of iron and suppression of erythropoiesis rather than an exacerbation of gross iron deficiency. We tentatively conclude that, if it is to be recommended, universal iron supplementation in malarious areas should only be considered in conjunction with some form of prophylaxis (e.g., intermittent preventive therapy [IPT]) or in the context of good health services with ready access to facilities for malaria diagnosis and treatment. An alternative approach would be to screen for anemia and target supplementation only to anemic children. With regard to treatment, there is good evidence that iron supplementation should be withheld until the treatment schedule is complete, both because iron may inhibit treatment and because the absorption of oral iron is blocked by the inflammatory response.
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PMID:Iron metabolism and malaria. 1829 91

Imbalances of iron homeostasis cause frequent clinical syndromes. Iron deficiency affects almost 25% of the global population and approximately one billion people suffer from iron deficiency anaemia. Moreover, the anaemia of chronic disease, which develops primarily in subjects suffering from malignancies, infections and autoimmune disorders is pivotally caused by an iron-limited erythropoiesis, which arises from iron retention within cells of the reticulo endothelial system. In contrast, one of the most frequent inherited disorders in people of Northern-Western European origin is hereditary hemochromatosis (HH). HH leads to progressive iron overload in parenchymal organs with subsequent organ failure. In addition, secondary iron overload develops in patients receiving repetitive blood transfusion for the treatment of genetic hemoglobinopathies or for the correction of anaemia in cancer or myelodysplastic syndromes. Due to the discovery of new genes, our knowledge on the regulation of iron homeostasis has dramatically expanded which offers avenues for new treatment options. This is of importance, since some of these clinical syndromes (e.g. anaemia of chronic disease or secondary iron overload) are not sufficiently treatable with current medications (e.g. iron chelators, iron, erythropoietin) in many patients. In addition, some patients with iron deficiency face side effects from iron therapy or refuse phlebotomy for treatment of HH. Thus, new treatment strategies for iron metabolism disorders or improvement of existing concepts are necessary. This review discusses established, approaching and future putative treatment strategies and concepts for combating iron metabolism disorders.
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PMID:New pharmacological concepts for the treatment of iron overload disorders. 1919 23

Previous short-term supplementation studies showed no additional hematologic benefit of multiple micronutrients (MMN) compared with iron + folic acid (IFA) in adolescent girls. This study examines whether long-term once- or twice-weekly supplementation of MMN can improve hemoglobin (Hb) and micronutrient status more than twice-weekly IFA supplementation in anemic adolescent girls in Bangladesh. Anemic girls (n = 324) aged 11-17 y attending rural schools were given once- or twice-weekly MMN or twice-weekly IFA, containing 60 mg iron/dose in both supplements, for 52 wk in a randomized double-blind trial. Blood samples were collected at baseline and 26 and 52 wk. Intent to treat analysis showed no significant difference in the Hb concentration between treatments at either 26 or 52 wk. However, after excluding girls with hemoglobinopathy and adjustment for baseline Hb, a greater increase in Hb was observed with twice-weekly MMN at 26 wk (P = 0.045). Although all 3 treatments effectively reduced iron deficiency, once-weekly MMN produced significantly lower serum ferritin concentrations than the other treatments at both 26 and 52 wk. Both once- and twice-weekly MMN significantly improved riboflavin, vitamin A, and vitamin C status compared with IFA. Overall, once-weekly MMN was less efficacious than twice-weekly MMN in improving iron, riboflavin, RBC folic acid, and vitamin A levels. Micronutrient supplementation beyond 26 wk was likely important in sustaining improved micronutrient status. These findings highlight the potential usefulness of MMN intervention in this population and have implications for programming.
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PMID:Long-term intermittent multiple micronutrient supplementation enhances hemoglobin and micronutrient status more than iron + folic acid supplementation in Bangladeshi rural adolescent girls with nutritional anemia. 2070 45

The prevalence of adolescent anemia, iron deficiency and thalassemia were examined in 2 provinces of northeast Thailand. Blood specimens were collected from adolescent subjects aged 15-17 years in 2 areas; 185 (85 males and 100 females) in Mukdahan province and 313 (116 males and 197 females) in Roi-Et. RBC parameters, serum ferritin levels, Hb and DNA analyses for the identification of common thalassemia genes in Thailand were investigated. The prevalences of anemia were found to be 21.1% (8.1 in male and 13.0 in female) and 16.6% (8.9 in male and 7.7 in female) in Mukdahan and Roi-Et province, respectively. Iron deficiency was observed to be 24.3% in Mukdahan and 14.7% in Roi-Et. Various types of thalassemia were identified in 62.2 and 58.8% of the subject populations, respectively. The proportions of iron deficiency, thalassemia and combined thalassemia and iron deficiency among anemic subjects were 10.2, 53.8 and 30.8% in Mukdahan, and 7.7, 67.3 and 9.6% in Roi-Et. Hematological characteristics were analyzed and are presented. It is concluded that thalassemia and hemoglobinopathies rather than iron deficiency are major causes of adolescent anemia which should be taken into account in public health strategies for the control of anemia in the region.
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PMID:Anemia, iron deficiency and thalassemia among adolescents in Northeast Thailand: results from two independent surveys. 2122 65

Refugee children, although in generally good health, may present with unfamiliar infectious or hematological problems, primarily tuberculosis, hepatitis B, intestinal parasites, malaria, eosinophilia and anemia. Prevalence, clinical features and treatment are discussed, together with the features of some less common infections. In the symptomatic refugee child, both common and exotic infectious diseases should be considered in the differential diagnosis. Iron deficiency and hemoglobinopathies should be considered in the differential diagnosis of microcytic anemia.
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PMID:Infections in refugee children from developing countries. 2127 54


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