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

Prenatal diagnosis of the hemoglobinopathies has been increasingly reported. This article discusses those ethical issues stemming from pregnancy studies by fetoscopy or placental aspiration: diagnostic accuracy and safety for mother and fetus, abortion of the fetus diagnosed as homozygous for thalassemia or sickle cell diseases, and access to prenatal diagnosis for those who cannot afford it. The author's position on these issues attempts to mediate between the poles in current ethical debate on abortion in public policy.
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PMID:Prenatal diagnosis of the hemoglobinopathies: ethical issues. 47 61

Fetoscopes are now being developed which make possible the inspection of human fetuses as well as withdrawal of a fetal blood sample in the early mid-trimester of pregnancy. The preliminary experiences of several groups are presented in this report. In addition, a fetoscopy including fetal blood sampling in a 24 week pregnancy prior to therapeutic abortion is described. The first prenatal diagnoses which have been made using this novel technique, concern defects of the fetal erythrocytes (sickle cel Hb, thalassemia). The fetal blood sample that was obtained in the present case was studied by appropriate methods. As expected, there was no evidence of either of these anomalies.
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PMID:[Fetoscopy. A new method in prenatal diagnosis (author's transl)]. 81 96

S-Homozygotes, SC heterozygotes, and S-beta-thalassaemia heterozygotes are the haemoglobinopathies which make up sickle cell disease. Although their clinical features are similar, as regards complications during pregnancy, Hb S-beta-thalassaemia most dangerous, the main causes of mortality being severe anemia, acute sequestration crisis, bacterial infections, painful episodes, and pulmonary bone marrow fat embolism. Folic acid and antimalarials (where these are indicated) are often successful in preventing severe anaemia. It is best to reserve blood transfusion to replace moderate loss or to correct gross anaemia quickly when this is considered severe enough to threaten life. Painful crises are particularly common towards the end of pregnancy and in treating these episodes, analgesics, antibiotics, and sometimes heparin are used. S-homozygote carries additional hazards. Because of the prevalence of pelvic contraction, fetopelvic disproportion is common and so the incidence of operative deliveries is high. Many fetuses are lost through an increased incidence of abortion and perinatal mortality. In the survivors, there is evidence of intrauterine growth retardation brought about by continuous maternal anaemia throughout pregnancy.
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PMID:Sickle cell disease in pregnancy. 126 39

In Southeast Asia alpha-thalassemia, beta-thalassemia, hemoglobin (Hb) E and Hb Constant Spring are prevalent. The gene frequencies of alpha-thalassemia reach 30-40% in Northern Thailand and Laos. beta-Thalassemia gene frequencies vary between 1 and 9%. Hb E is the hallmark of Southeast Asia attaining a frequency of 50-60% at the junction of Thailand, Laos, and Cambodia. Hb Constant Spring gene frequencies vary between 1 and 8%. These abnormal genes in different combinations lead to over 60 different thalassemia syndromes. The four major thalassemic diseases are Hb Bart's hydrops fetalis (homozygous alpha-thalassemia 1), homozygous beta-thalassemia, beta-thalassemia/Hb E and Hb H diseases. The molecular basis of most of these abnormal genes have been recently described. Therefore, it is possible to set a strategy for prevention and control of thalassemia which includes population screening for heterozygotes, genetic counseling and fetal diagnosis with selective abortion of affected pregnancies.
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PMID:Thalassemia in SouthEast Asia: problems and strategy for prevention and control. 129 71

Mass screening of married couples in the town of Baku has revealed a couple at risk of giving birth to a child with homozygotic beta-thalassemia. Prenatal diagnosis was carried out during week 23 of pregnancy by means of cordocentesis and biochemical analysis of globin chains, in vitro synthesized in fetal blood in the presence of labeled leucin. beta-thalassemia was detected in the fetus, similarly as in the child in this family. Abortion was induced on pregnancy week 25. Prenatal diagnosis is recommended in case of another pregnancy during the first trimester, involving analysis of the chorionic villi DNA.
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PMID:[Prenatal diagnosis of beta-thalassemia]. 183 13

By means of polymerase chain reaction (PCR), prenatal diagnoses were successfully made in 20 fetuses at risk for beta-thalassemia homozygotes and 2 at risk for Bart's hydrops fetalis. Six pregnancies with homozygotes or double heterozygotes of beta-thalassemia were therapeutically terminated. Ten fetuses were predicted to be beta-thalassemia heterozygotes and 4 were normal. Hydrops fetalis was excluded in two fetuses. The predictions have so far been confirmed after delivery or therapeutic abortion, and no discrepancy was found. The advantages of this technique are discussed.
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PMID:[Rapid prenatal diagnosis for thalassemia]. 183 57

The reproductive behaviour of couples with heterozygous beta thalassaemia, with at least one affected child, was investigated for the period 1955 to 1984 and was compared to the behaviour of control couples matched for age, age at marriage, and presence of at least one child. The comparisons were made as a function of knowledge of the risk and availability of prenatal diagnosis and abortion. It was found that the couples segregating for Cooley's anaemia, before knowledge of the risk, had a higher reproductive rate than that of control couples. Knowledge of the genetic risk had a different effect on reproductive behaviour in the 1950s from that in later years. The difference was attributed both to the influence of cultural factors and to technical, therapeutic, and diagnostic advances.
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PMID:Reproductive behaviour of families segregating for Cooley's anaemia before and after the availability of prenatal diagnosis. 192 Mar 67

In this review, we describe a simple strategy to detect the three severe thalassemic diseases commonly found in Thailand. Hb Bart's hydrops fetalis can be detected unambiguously by ultrasonography at 18-20 weeks of gestation or detected early in the first trimester by the gene amplification technique. Prenatal diagnosis for homozygous beta-thalassemia is better performed in the second trimester by in vitro protein synthesis. This is because the molecular defects of some beta-thalassemias are still unknown and homozygosity of the same mutation is low. In contrast, beta-thalassemia/Hb E is easily detected, in the first trimester, by direct visualization on electrophoresis or by dot blot analysis of enzymatically amplified DNA with a set of nonradioactively labeled oligonucleotide probes complementary to the most common mutations. We also found that the beta/gamma synthesis ratio in homozygous Hb E is similar to that of beta-thalassemia/Hb E and DNA analysis is the only method to distinguish these two conditions in the couple at risk of having either beta-thalassemia/Hb E or asymptomatic homozygous Hb E. In 100 pregnancies studied, the diagnoses were achieved in 96 pregnancies. Complications leading to fetal loss were found in 3 pregnancies: one woman developed amnionitis after fetal blood sampling; one had amniotic fluid leakage after the biopsy, and the third, carrying a normal fetus, aborted 10 days after fetal blood sampling with urinary tract infection and high fever. However, these figures are compatible with other reports and the risks are significantly lower than that of thalassemic disease the fetus is facing. One case of beta-thalassemia/Hb E was incorrectly diagnosed prenatally as being Hb E trait. In twenty-five pregnancies (25%) prenatally diagnosed to carry affected fetuses it was decided to have abortion. This study shows the feasibility of prenatal diagnosis for thalassemic diseases in Thailand which, in addition to screening and genetic counseling, can support prevention and control programs for thalassemia.
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PMID:Prenatal diagnosis of thalassemia and hemoglobinopathies in Thailand: experience from 100 pregnancies. 194 58

Early amnion rupture is a sporadic event that results in mechanical teratogenesis due to amniotic-band disruption and/or compression. It may cause abortion or stillbirth, craniofacial clefts, and cerebral, body wall and limb/skeletal defects. Prolonged and premature rupture of membranes and oligohydramnios result in the dry-lung syndrome and pulmonary hypoplasia. The risk of chorioamnionitis is also increased, with serious consequences to the fetus and neonate. Placental lesions are associated with fetal growth retardation, preterm birth, fetal malformations and other neonatal disorders (congenital infections, erythroblastosis, alpha thalassaemia). In particular, the impact of extremely preterm births on perinatal mortality rates and health costs is substantial. The 1-year survival rate of singleton infants born at the Monash Medical Centre was 10% at a gestation period of 23 weeks, 37% at 24 weeks, 42% at 25 weeks, 61% at 26 weeks and 78% at 27 weeks (11% at birthweights of 500-599 g, 30% at 600-699 g, 55% at 700-799 g and 71% at 800-899 g). Proven measures to minimize the neonatal consequences of extremely preterm delivery include in utero transfer of at-risk fetuses to a perinatal centre and antepartum corticosteroids. Research into the pathophysiological basis of placental and membrane dysfunction may help reduce the prematurity rate.
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PMID:Neonatal consequences of placental and membrane dysfunction. 195 32

The challenges in the control of genetic disorders will be to provide pediatric surgery, continuous medical or social support, and research. The focus of this report is on the factors influencing the relevance of genetics programs for public health: genetic epidemiology, genetic structure, demographic factors, and the level of development of the country. Approaches for control of genetic diseases must accept that prevention and treatment are usually impossible. The only remaining alternative is avoidance through genetic counseling and genetic counseling and genetic screening neonatally, or before and during pregnancy with ultrasound or alpha fetoprotein serum screening. Some pregnancies at risk may be identified by advanced maternal age distribution and country. There is also the possibility of premarital carrier detection, which has been successful in the identification of thalassemia in Cyprus. Carrier detection can occur both before and during pregnancy for groups at risk for Tay-Sachs disease, sickle cell disease, and thalassemia. In the future, there may be carrier tests available for certain common inherited diseases such as cystic fibrosis. Fetal diagnosis ensures the delivery of a healthy child for some conditions. Thus far amniocentesis, fetal blood sampling, and chorionic villus sampling do not indicate an excessive rate of fetal loss, but laboratory diagnosis is dependent on accuracy of readings. Cytogenetic, biochemical, and DNA methods need improvement. The limitation of fetal diagnosis is that the only avoidance option is abortion. Problems also exist in the delivery of genetic services. Based on existing services in Europe, no more than 20% of the genetic burden is avoided, unless there is good public education an counseling at the community level. Obstetricians and practicing physicians need training in genetic counseling. Professional codes of practice need to be instituted. The effectiveness of control measures is dependent on the strategy adopted and must pertain to the country-specific needs. A monitoring body may be required to ensure fairness, effectiveness, and improvement in service delivery. Appropriate nutritional and public health strategies need to be formed to account for the genetically determined population differences, i.e., lactose intolerance, G6PD deficiencies, or hemoglobin E/Beta thalassemia, for all diseases have a genetic determinant.
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PMID:Problems in the control of genetic disorders. 213 Sep 14


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