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 histological features of thalassemic bone are imperfectly known, and the roles of bone marrow hyperactivity, iron overload or vitamin D deficiency in the pathogenesis of the disease are not clearly identified. In this study we examined iliac crest biopsies from 17 transfusion-dependent children with homozygous beta-thalassemia and severe radiological skeletal thalassemic changes, including widening of medullary spaces and osteoporosis. Rachitic lesions were not observed. Serum ferritin concentrations were increased in all but one subject. Iron deposits were histochemically detected in bone marrow, at the marrow-bone interface, along cement lines and mineralizing perimeters. Minor changes were present in trabecular bone, and osteomalacia was absent. By contrast, cortical bone exhibited severe changes including fissures and focal mineralization defects. Plasma 25-hydroxyvitamin D (25(OH)D) concentrations measured during the winter (December-May, 6.5 +/- 4.9 ng/ml, mean +/- SD, n = 6) and during the summer (June-November, 13.8 +/- 8.4 ng/ml, n = 9) did not differ from those of age-matched children living in the same country. Seven patients had moderate hypocalcemia but no biological signs suggestive of vitamin D deficiency: all had normal alkaline phosphatase activity, normal or slightly elevated plasma phosphate, only two had low plasma 25(OH)D concentrations and two others supranormal values of plasma immunoreactive parathyroid hormone. These results show that iron overload and vitamin D deficiency do not seem to play an important role in the pathogenesis of thalassemic bone disease, which is characterized by cortical lesions probably related to marrow hyperactivity.
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PMID:Bone disease in children with homozygous beta-thalassemia. 230 56

Four female patients with thalassemia intermedia developed secondary acetabular protrusion. These cases could be the first reported cases of nontraumatic acetabular protrusion in patients with thalassemia. The rarified pelvic bone may be due to medullary hyperplasia, iron overload, or disordered calcium metabolism in conjunction with osteomalacia. The fact that currently patients with beta-thalassemia have a longer life expectancy may explain the recent observation of this entity, which should become more familiar to orthopedic surgeons who treat thalassemia patients in the future.
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PMID:Acetabular protrusion in thalassemia. A report of four cases. 232 31

Painful, crippling deformities in Tanzanian children from an area of endemic fluorosis are reported. Excessive fluoride ingestion in pregnant women may possibly poison and alter enzyme and hormonal systems in the fetus causing disturbances to osteoid formation and mineralization. Knock-knees, bowlegs, and saber shins develop when walking begins. Combinations of osteomalacia, osteoporosis, and osteosclerosis result in a spectrum of bone changes from an early age. Male hormones, and dietary and genetic deficiencies may aggravate individual response of actively growing bones. Some radiographic changes suggestive of rickets, hyperparathyroidism and thalassemia were observed.
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PMID:The spectrum of radiographic bone changes in children with fluorosis. 738 28

Thalassemia/hemoglobinopathy is a hereditary disease that causes chronic anemia and increased erythropoiesis. Consequently, an expansion of bone marrow spaces may contribute to osteopenia/osteoporosis. However, the pathogenesis of bone changes is not yet known. We, therefore, carried out the study on bone histomorphometry and biochemical and hormonal profiles in children and adolescents with suboptimally treated beta-thalassemia disease with the hope of gaining some new insight into the cellular and structural alterations of thalassemic bone. Seventeen patients underwent iliac crest bone biopsy for histomorphometric analyses. Bone mineral density (BMD) measurements were performed by dual energy x-ray absorptiometry. Most patients had growth retardation and delayed bone age. BMD was low especially at the lumbar spine. Serum IGF-I levels were almost always low. Bone histomorphometry revealed increased osteoid thickness, osteoid maturation time, and mineralization lag time, which indicate impaired bone matrix maturation and defective mineralization. In addition, iron deposits appeared along mineralization fronts and osteoid surfaces. Moreover, focal thickened osteoid seams were found together with focal iron deposits. Dynamic bone formation study revealed reduced bone formation rate. These findings indicate that delayed bone maturation and focal osteomalacia are the pathogenesis of bone disease in suboptimally blood-transfused thalassemics with iron overload. Iron deposits in bone and low circulating IGF-I levels may partly contribute to the above findings.
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PMID:Bone histomorphometry in children and adolescents with beta-thalassemia disease: iron-associated focal osteomalacia. 1291 94

Bone disease in thalassemia in the form of low bone mass remains a frequent, debilitating and poorly understood problem, even among well transfused and chelated pre-pubertal and adult patients. In this work we attempted to delineate calcium status and bone mineral density in a group of transfusion dependent thalassemic adolescents of both sexes. Bone mineral density (BMD) at both the lumbar spine and femoral neck was measured in 40 adolescents with beta thalassemia major (TM) by DXA scanning and correlated to biochemical parameters including calcium, phosphorus, alkaline phosphatase, bone alkaline phosphatase, intact parathyroid hormone and 25-OH vitamin D as well as vitamin D receptor (VDR) gene polymorphisms at exon 2 (Fok1). Z-score of BMD at the lumbar spine (-3.3, +/-1.4) was significantly lower than at the femoral neck (-0.68, -/+1.3), (p=0.001). Serum ferritin and VDR genotype were related to BMD only at the femoral neck indicating that the factors determining the BMD at these 2 sites might be different. Seventy-five percent of patients had a low calcium level and hypoparathyroidism was present in 72.5% of patients. The low calcium level was probably caused by a combination of hypoparathyroidism and osteomalacia evidenced by elevated bone alkaline phosphatase presumably resulting from deficient calcium intake. To optimize BMD in TM, it is important to ensure adequate iron chelation and adequate intake of calcium and vitamin D.
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PMID:Bone mineral density and calcium metabolism in adolescents with beta-thalassemia major. 1933 66

Quantitative ultrasound (QUS) of the bone is a technique that is generating great interest among bone structure researchers because of its intrinsic features. Its safety and low cost make it an ideal technique for repeated measurements over time such as in chronic disease or when it is necessary to monitor the effects of prescribed therapies. The method was developed for the study of osteoporosis and the sites of measurement are all peripheral, including the distal diaphyses and metaphyses of the phalanges, calcaneus, radius and tibia. QUS parameters, however, cannot be used directly for the diagnosis of osteoporosis according to the WHO criteria, although many authors have shown that ultrasound parameters, particularly those of calcaneal QUS, can predict the risk of osteoporotic fractures independently of MBD. Very promising results with the use of QUS have been obtained in corticosteroid-induced osteoporosis, rheumatoid arthritis, Cushing's syndrome, cystic fibrosis, osteomalacia, thalassemia and osteopenia related to parenteral nutrition. QUS can also monitor the effectiveness of therapy in various pathological conditions. In nephrology the combined use of phalangeal QUS and biochemical markers of bone turnover allows adequate follow-up of patients on dialysis and renal transplant recipients with alterations or disorders of the bone.
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PMID:[Bone ultrasonography in kidney disease: applications and limitations]. 2322 31