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Query: UMLS:C0039730 (thalassemia)
 10,305 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

This report discusses the role of prenatal screening in preventing congenital abnormalities or, when prevention is not possible, in avoiding the conception or the birth of those who would have untreatable abnormalities. Women who are found by screening not to be immune to rubella can be safely vaccinated prior to pregnancy; those found to be at risk of having children with genetic disorders such as Tay-Sachs disease or thalassemia have the option of avoiding the conception of affected offspring. Screening during pregnancy permits the primary prevention of Rh disease and its sequelae when it results in the prophylactic administration of Rh-immune globulin to unsensitized Rh-negative women. Maternal serum alpha-fetoprotein screening identifies pregnant women who are at increased risk of carrying fetuses with neural tube defects or Down's syndrome, giving them the option of avoiding the birth of affected fetuses through abortion. Recombinant DNA technology will permit screening for many more genetic disorders as the disease-related genes and mutations are identified. For many of these disorders, the ability to predict the risk of disease will antedate preventive and therapeutic interventions by many years. During this lag phase, issues concerning the validity of the tests, the severity of the conditions for which screening is offered, the safety of the interventions, and the autonomy of the pregnant women in deciding to be screened are important.
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PMID:Prenatal screening: when and for whom? 214 72

alpha-Thalassaemia is a disturbance of the alpha-chain synthesis of the haemoglobin, which occurs mostly in the Far East. On account of the total absence of alpha-chains, the homozygous form is considered to be fatal. However, beta and lambda chains exist abundantly. Abortion, intrauterine or perinatal death are the results of the extreme anaemia (Hb-Bart's syndrome), despite modern intensive medical care. The prenatal diagnosis is possible by: 1. DNA analysis of material obtained by chorion villi sampling or culture of fibroblasts, when a risk of re-occurrence is known to the physician. 2. Hb-electrophoresis from foetal blood in cases of hydrops of uncertain origin. When the diagnosis of this fatal disease is established, there is no foetal indication for delivery by Caesarian section.
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PMID:[Alpha-thalassemia as a rare differential diagnosis of hydrops fetalis et placentae]. 228 18

Recent advances in prenatal diagnoses of sickle cell anemia and thalassemia permit early identification of affected fetuses. However, the only intervention possible to date is abortion of the affected fetuses. Transplantation of normal marrow into fetuses in utero could correct these life-threatening disorders, but to accomplish this techniques must be developed for fetal transplantation in man. Therefore, we have transplanted fetal baboons with mismatched adult baboon bone marrow from donors that differed at the glucose phosphate isomerase locus. Twenty-two fetuses between 60 and 160 days of gestation (term gestation is 182 days) were transplanted intraperitoneally with 10(9) marrow mononuclear cells/kg body weight using an ultrasonic technique. No immunosuppressive or preparative regimen was given prior to or after transplantation, and all fetuses tolerated the procedure well. One month after transplantation fetal blood samples were obtained to assess chimerism. Three chimeras were detected among 10 fetuses transplanted at 80 days' gestation, and no chimeras were detected in fetuses greater than 80 days' gestation at the time of transplantation. All chimeras died in utero during the third trimester of pregnancy: one of an intrauterine infection at 160 days' gestation, one at 135 days' gestation and one at 145 days' gestation. In contrast, the other 19 non-chimeric fetuses survived. These data suggest: (1) in utero fetal bone marrow transplantation is technically feasible in primates; (2) that allogeneic adult bone marrow can engraft and persist for at least 1 month in fetal baboons transplanted at 80 days of gestation; and (3) that delineation of the causes for loss of fetal chimeras should prove valuable in assessing the therapeutic potential for in utero bone marrow transplantation in man.
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PMID:In utero bone marrow transplantation of fetal baboons with mismatched adult marrow: initial observations. 304 78

A non-directive programme of prenatal counselling was used during a four year period. Forty-three couples at risk for having a baby with a haemoglobinopathy were identified. Prenatal diagnosis was offered in 19 pregnancies to 14 couples at risk of having a baby with sickle cell anaemia and in two pregnancies in two couples at risk of a baby with beta thalassaemia major, who presented before the 18th week of pregnancy. Six couples at risk for sickle cell anaemia accepted prenatal diagnosis in 10 pregnancies, as did both couples at risk for thalassaemia. Couples who were eligible for prenatal diagnosis but refused it tended not to have been informed about sickle cell disease before counselling, one partner was more frequently absent at the time of the initial counselling session, or they either had no children with sickle cell disease or the children were not severely affected. Other factors influencing their decision included a poor obstetric history and rejection of abortion, mainly on moral grounds. The approximately 50% uptake of prenatal diagnosis in this initial study highlights the complex issues involved. Our experience indicates that with systematic screening and counselling in the antenatal clinic, and with increased awareness of the haemoglobinopathies, couples at risk will be in a better position to make informed decisions.
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PMID:Counselling for prenatal diagnosis of sickle cell disease and beta thalassaemia major: a four year experience. 323 57

Forty-six hydropic infants with homozygous alpha-thalassaemia born during a period of 10 years have been reviewed. The incidence was 1:1550 total births, and accounted for 81% of all non-immune hydrops. The male to female ratio was 1:1.4. There was increased incidence of anaemia, pregnancy induced hypertension, antepartum haemorrhage, malpresentation, prematurity, fetal distress, difficult vaginal delivery, caesarean section, retained placenta, postpartum haemorrhage and congenital abnormalities. Antenatal diagnosis by DNA hybridization with subsequent abortion of the affected fetuses is the best method to decrease maternal morbidity and to reduce the incidence of hydrops fetalis in couples at risk. For those with no previous history, but with early onset hypertension and/or polyhydramnios, sonography is useful in making an earlier diagnosis, and in reducing avoidable morbidity, because DNA analysis can be done before caesarean section and aggressive neonatal management is instituted.
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PMID:Homozygous alpha-thalassaemia: clinical presentation, diagnosis and management. A review of 46 cases. 401 25

A programme of prospective heterozygote detection and counselling, fetal diagnostic testing, and abortion of fetuses affected by thalassaemia major introduced in Britain in 1977 has proved highly acceptable to at-risk couples of Cypriot and East African Asian origin, but less so to couples of Pakistani origin. However, many at-risk couples are still not detected prospectively, the proportion of thalassaemia-major births prevented was only 32% by the end of 1981, and there is little evidence of a further fall since then. The thalassaemia-major birth-rate had fallen by 60% in Cypriots and by 20% in East African Asians, but it had not fallen at all in Pakistanis. Improved approaches to fetal diagnosis of thalassaemia major are becoming available, so a concerted effort is needed to inform all the at-risk ethnic groups of the existence of the problem and the possibility of detection of affected fetuses.
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PMID:Effect of fetal diagnostic testing on birth-rate of thalassaemia major in Britain. 615 Mar 77

Isoelectric focusing (IEF) of hemoglobin was compared to the classical chromatography of labeled globin chains for 22 antenatal diagnoses of hemoglobinopathies: 11 for beta thalassemia, and 11 for sickle cell disease. In all cases, the two methods gave identical results. The diagnosis was confirmed after birth or abortion. Three fetuses homozygous for beta thalassemia and one homozygous for sickle cell disease exhibited no Hb A by IEF, in contrast to normal fetuses or those heterozygous for one of the two hemoglobinopathies. In addition, blood samples obtained in other centers after abortion of 22 fetuses homozygous for beta + or beta 0 thalassemia exhibited no Hb A when analyzed by IEF. When Hb A was present, the respective proportions of Hb A and acetylated Hb F were determined by densitometry of the IEF gel. The Hb A/acetylated Hb F ratio obtained by IEF correlated well with the beta A/gamma ratio of globin chain synthesis, IEF requires 0.1 mg of unlabeled hemoglobin. It is performed in 90 min and several samples can be analyzed simultaneously. If present, maternal contamination of fetal blood must be eliminated by selective lysis of maternal (RBC) using the Orskov reaction. Improvements in this method to obtain suitable samples for IEF analysis are described.
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PMID:Prenatal diagnosis of hemoglobinopathies: comparison of the results obtained by isoelectric focusing of hemoglobins and by chromatography of radioactive globin chains. 615 34

At Cabras (Oristano), a town characterized by a high incidence of thalassaemia and G6PD deficiency less than half the people between 18 and 35 have a fair knowledge of genetic diseases and of their prevention. The lack of information is higher among people working in the primary sector, housewives and generally, among those who are uneducated. The majority of the people we have interviewed are favourable to undergo analysis to single out carriers. Of these many have said to be unwilling to give birth to children if they belong to a couple at risk. Other have said they do not exclude of having children all the same but to be willing to amniocentesys, and to miscarriage if necessary. From a total calculation results that 88,03% of the men and 82,18% of the women we have interviewed would use, as a prevention, the information obtained from a genetic centre.
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PMID:[The client's viewpoint on genetic counseling. Acceptability of the service in an Oristanese community (Cabras)]. 621 76

The most important haemoglobinopathies in developing countries are reviewed in the light of new results elicited with modern research approaches. It has been shown that the sickle mutation originating in a localized region in West Africa arose independently of the mutation in East Africa and Asia. The frequency of alpha-thalassaemia has been underestimated in mediterranean and African countries. The inherited resistance to Plasmodium falciparum in the sickle cell disorders and thalassaemia has been elucidated to a large extent. The heterogeneity of alpha- and beta-thalassaemia has been investigated at the molecular level of the globin genes. Clinical management with repeated blood transfusions and regular iron chelation has markedly improved life expectation of the patient with thalassaemia major. Screening and educational programmes on a large scale in combination with facilities for genetic counselling, prenatal diagnosis and therapeutic abortion have already reduced the incidence of serious haemoglobinopathies in several developed countries. However, these methods will not be available for the population of developing areas until these countries reach a generally higher level, both economically and socially.
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PMID:[Hemoglobinopathies in developing countries]. 638 6

We report here an evaluation of a program for thalassemia-disease prevention, comprising education, population screening for heterozygotes, and reproductive counseling; the evaluation includes cost analysis. A preprogram survey in 1978 of 3,247 citizens in the high-risk communities (85% were high-school students) showed that 88% favored a program but that only 31% considered fetal diagnosis as an acceptable option. Screening in high school or before marriage was preferred by 56%. In a 25-month period (December 1979-December 1982), we screened 6,748 persons, including 5,117 senior high-school students, using MCV/HbA2 indices. The participation rate was 80% in the high-school group. The frequency for beta-thalassemia heterozygosity was 4.7% with 10-fold variation among ethnic groups at risk; the overall frequency for all variants found was 5.4%. We surveyed 60 carriers and 120 noncarriers after screening high-school students (response rate 77%): most carriers told parents (95%) and friends (67%) the test result; and 38% of the carriers' parents (vs. 18% of the noncarriers' parents) were also screened. Carriers would ascertain their spouses' genotype (91%) and approved uniformly (95%) the high-school screening experience and its goal. We performed 11 fetal diagnoses in a 25-month interval (greater than 75% participation in target population) either by fetoscopy and globin-chain analysis or by amniocentesis and genomic DNA analysis; two of three affected fetuses were aborted at parental request, there was one spontaneous abortion (after fetoscopy), and seven live births. The at-risk couples claimed pregnancy would not be contemplated without the fetal-diagnosis option. We analyzed economic costs of the program: cost per case prevented is approximately equal to $ 6,700, slightly less than cost-per-patient-treatment-year or about 4% of undiscounted treatment cost incurred in the first 25 years of life for an affected individual. These findings indicate: collective acceptance of the program, appropriate attitudes among carriers, general acceptance and efficacy of fetal diagnosis, and global cost-effectiveness.
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PMID:Beta-thalassemia disease prevention: genetic medicine applied. 649 71


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