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Antenatal intrauterine diagnosis of fetal thalassaemia.

The results are reported of the intrauterine diagnosis of fetal thalassaemia in 72 pregnant women investigated during the six years from 1977 to 1982. In the majority of cases fetal blood was collected by fetoscopy for globin chain synthesis at 18 to 19 weeks' gestation. Adequate fetal blood samples for the diagnosis of the thalassaemia status of the fetus were obtained in 85% of cases. The technical difficulties associated with fetoscopy and fetal blood collection are discussed, and the maternal and fetal complications of the procedure described.

Blood Chemical Analysis↗

[Prenatal diagnosis in dermatology: contribution of the ultrastructural study].

Fetoscopy and fetal skin biopsy have together played an important role for antenatal diagnosis of various hereditary skin disorders (genodermatoses). The fetus and placenta can be visualized directly and skin biopsy samples can be obtained for light and electron microscopic studies, tissue culture and biochemical analysis. These techniques have been used successfully in the prenatal diagnosis or exclusion of some types of epidermolysis bullosa, ichthyosis, Chediak-Higashi syndrome, oculocutaneous albinism and anhydrotic ectodermal dysplasia in fetuses known to be at risk from these diseases. The purpose of this report is to describe the current methods of fetoscopy and fetal skin biopsy and to review their main dermatological indications. Complications associated with these procedures are also discussed.

Biopsy↗

[Prenatal diagnosis of congenital anomalies--present status and future problems].

Technical advances continue to expand the number of genetic disorders that can be diagnosed in utero. The current methods for prenatal diagnosis are as follows: Amniocentesis, fetoscopy, fetal blood sampling, biopsy of fetal skin, and chorionic villus sampling (CVS). The method for growing fetal cells obtained by amniocentesis in short term culture and karyotyping has opened a new area to chromosomal anomalies. By using cultured amniotic fluid cells in larger numbers, it is also possible to diagnose many metabolic disorders. Fetoscopy has been developed which permits the perinatologist to enter the uterus and obtain tissue sample or to actually view the fetus. However, it is very difficult to visualize the fetus directly through fetoscope. Only specific parts of the fetus can be readily identified, but a total examination of surface anatomy is rarely possible. Now ultrasonography with improved resolution can clearly define many major anatomical abnormalities without apparent risk. And also, fetal blood sampling and skin biopsy have been successfully performed under ultrasound guidance rather than under direct fetoscopic visualization. Recently, the advent of fetal blood sampling has made it possible to diagnose genetic disorders which have hitherto been impossible to recognize in the fetus. The main applications are for the prenatal diagnosis of the fetal infection, coagulopathies, hemoglobinopathies, and muscular dystrophies. Several severe genodermatoses result in early death or are associated with significant morbidity. Some of these disorders can be diagnosed in utero with skin biopsies. Harlequin Ichthyosis is a typical case. A positive prenatal diagnosis of Harlequin Ichthyosis was reported.(ABSTRACT TRUNCATED AT 250 WORDS)

Amniocentesis↗

Prenatal diagnosis of beta-thalassemia.

Prenatal diagnosis was attempted in 14 fetuses at risk for homozygous beta-thalassemia, gestational age 18-22 weeks. In 4 cases the placenta was entirely anterior, placental aspiration under ultrasonic control only had to be used for fetal blood sampling. In 10 fetuses fetoscopy was used for puncture of a chorionic blood vessel. Diagnoses were based on the rate of in vitro synthesis of beta-globin related to total non-alphaglobin synthesis. With the aid of fetoscopy, nearly pure fetal blood was obtained in general. Placental aspiration resulted in samples which contained a low percentage of fetal and a high percentage of maternal cells. The attempt of fetal blood sampling resulted in fetal loss in two cases. In 2 aspiration cases no diagnosis could be made because the samples were inadequate. In 2 cases the diagnosis was established in spite of low fetal cell content through determination of the specific radioactivity in the placental and pure maternal blood. Until now 6 children have been born in whom prenatal diagnosis had been attempted, none of them has homozygous thalassemia. Present efforts are directed toward improving the safety of fetal blood sampling and the biochemical methods for the diagnosis in placental samples with low fetal cell content. Although the prenatal diagnosis of beta-thalassemia is possible, the procedure has still to be considered experimental.

Female↗

Does amniotic fluid analysis reflect acid-base balance in fetal blood?

OBJECTIVE: The purpose of the study was to examine whether the acid-base balance in amniotic fluid reflects the acid-base state in fetal blood. STUDY DESIGN: The pH, PCO2, PO2, bicarbonate, and base excess concentrations were measured in umbilical venous, umbilical arterial, and maternal venous blood and in amniotic fluid samples obtained at fetoscopy. This was performed before intraamniotic termination of 16 normal pregnancies (mean gestation 19.4 weeks), as well as in 14 red blood cell isoimmunized pregnancies (mean gestation 28.4 weeks) undergoing fetoscopy for the diagnosis and treatment of fetal anemia. RESULTS: In normal pregnancies, amniotic fluid pH and bicarbonate were significantly lower than umbilical venous and umbilical arterial blood concentrations, and this was due to the high concentration of base deficit in amniotic fluid. Whereas amniotic fluid PCO2 did correlate significantly with fetal umbilical venous PCO2 values, there was no correlation between other acid-base characteristics. CONCLUSION: Simultaneous sampling of human fetal umbilical blood and amniotic fluid under the acute conditions of this study did not show significant correlations in acid-base values.

Acid-Base Equilibrium↗

Endoscopic intrauterine fetal therapy: a monkey model.

OBJECTIVES: Prenatal ultrasonographic investigations have led to an increasing number of prenatally detected abnormalities, of which a large number involves the urogenital tract. This study was performed to evaluate if endoscopic intra-amniotic access is possible in primates. METHODS: In 10 midtrimester rhesus monkeys (Macaca mulatta), endoscopic intrauterine fetoscopy was performed with three access cannulas. Using a Seldinger technique, a vascular access system, and a pediatric laparoscopy set, intra-amniotic inspection was attempted. Fetal growth throughout pregnancy was monitored by ultrasonographic measurements of fetal biometry. RESULTS: Intrauterine access could successfully be achieved in 10 rhesus monkeys with three cannulas. After partial amniotic fluid exchange, adequate fetoscopy was always possible. Two monkeys aborted on the second and sixth postoperative days. Serial ultrasonographic investigations for fetal biometry showed no disturbance of the intrauterine growth patterns in the remaining 8 monkeys. CONCLUSIONS: We currently conclude that the rhesus monkey model for experimental intrauterine endoscopic surgery may be suitable for study of the developmental abnormalities of the genitourinary tract.

Animals↗

First-trimester three-dimensional ultrasonographic findings in a fetus with frontonasal malformation.

A case of a frontonasal malformation observed during the first trimester with three-dimensional ultrasonography and fetoscopy is reported. Absence of the nasal bone and a poorly characterized nose were visualized at 11 5/7 weeks by two-dimensional ultrasonography. Rendered three-dimensional ultrasound images revealed absence of the nasal bridge, widely spaced frontal bones and hypertelorism. Fetoscopy, performed at 12 3/7 weeks, confirmed the hypertelorism and showed a broad translucent nose with a flat nasal bridge. The final diagnosis of frontonasal malformation was made at autopsy after pregnancy termination. A review of prenatally diagnosed cases as well as the various syndromes having frontonasal malformation as a common denominator is presented.

Abnormalities, Multiple↗

How do carriers of hemophilia experience prenatal diagnosis (PND)? Carriers' Immediate and later reactions to amniocentesis and fetal blood sampling.

A semistructured personal interview was performed with 29 carriers of hemophilia A or B, 1-5 years after a pregnancy in which prenatal diagnosis (PND) was performed by fetal blood sampling. Fetal blood sampling by fetoscopy was significantly more often reported by the women to the more trying than expected than was ultrasound-guided heart puncture. Of 29 women 13 was classified as having experienced the PND process (amniocentesis and fetal blood sampling) as distressing, having had mental or psychosomatic symptoms associated with it. All of the women who had abortion/miscarriage after PND reported a very high frequency of psychological sequelae during the 6 months that followed PND. Of 22 women who continued their pregnancy with a healthy fetus after PND 8 experienced the period until delivery as trying and felt that their emotional and somatic status influenced their daily life activities. This was particularly common among women who after fetoscopy received routine profylactic terbutalin treatment and had continuous sickleave until the 36th gestational week, 17/29 would consider going through PND in the future. Qualified psychological assistance must be offered both before and after PND.

Adult↗

Ultrasound-guided fetal intravenous transfusion for severe rhesus haemolytic disease.

Intrauterine, intraperitoneal transfusion is associated with a poor survival rate in fetuses with hydrops and low gestational age. A method of direct fetal intravenous transfusion was used in two fetuses. One fetus with severe rhesus haemolytic disease was given transfusions in the 29th and 30th weeks of gestation, using an ultrasound-guided needle through the hepatic part of the umbilical vein without fetoscopy. In another fetus, an experimental cannulation of the umbilical vein succeeded in the 23rd week of gestation. Ultrasound-guided fetal intravenous transfusion avoids the use of fetoscopy, which has limitations, and may improve the prognosis for rhesus-sensitised fetuses.

Adult↗

Application of molecular genetics to prenatal diagnosis and carrier detection in the hemophilias: some limitations.

Prenatal diagnosis and carrier detection in the hemophilias have received much attention in recent years. The error rate in prenatal diagnosis by fetoscopy is less than 1%; fetoscopy is not possible, however, until the second trimester of pregnancy. Carrier detection based on bioassays of plasma has an irreducible error rate (approximately 5%?), because of the "lyonization" phenomenon in heterozygous women, and the final results are always probabilistic. New DNA methods promise to alleviate these difficulties. Prenatal diagnosis can be accomplished in the first trimester. "Lyonization" is bypassed in carrier detection, and the results may sometimes be essentially nonprobabilistic. But the DNA methods have certain limitations of their own which are not widely appreciated. Aside from cost and the necessity to adopt a new technology, there are inherent genetic problems: mothers must be heterozygous for both a disease gene and a marker gene, final results are probabilistic if the marker gene lies outside the disease gene, and multiple marker genes are often in linkage disequilibrium. We have concluded that a clinical unit planning to use the DNA methods must also maintain the conventional methods at a high level of performance.

Crossing Over, Genetic↗

[Antenatal diagnosis of hereditary epidermolysis bullosa].

Among the genetic disorders of the skin, the heterogeneous group of epidermolysis bullosa includes some of the most severe. Prenatal diagnosis is of considerable importance to the families who have had an affected child, or in which one of the parents is affected. The prenatal diagnosis is performed using fetoscopy and fetal skin biopsy. Fetal skin samples are taken at 20 weeks of gestation and are examined by light and electron microscopy to determine whether the fetus is affected. We report here the French experience on prenatal diagnosis of the severe inherited epidermolysis bullosae. Given the severity and frequency of Herlitz syndrome, it is not surprising that this is the most frequently encountered disease in our series of prenatal diagnosis (14 of 21 epidermolysis bullosae), followed by Hallopeau-Siemens (6 cases), and Pasini type (1 case). Our exclusion diagnosis of a Pasini fetus was the first prenatal diagnosis of this type of epidermolysis bullosa performed and reported in the literature. We stress here in this paper that observing the site of separation in the epidermal dermal junction is not sufficient to make a positive prenatal diagnosis. Prenatal diagnosis depends on the observation of the specific ultrastructural marker of the disease such as: hypoplasia and absence of hemidesmosomes and sub-basal dense plate in junctional epidermolysis bullosa-Herlitz, collagenolysis in recessive dystrophic epidermolysis bullosa-Hallopeau-Siemens, and absence and hypoplasia of anchoring fibrils in dominant dystrophic epidermolysis bullosa-Pasini. Until biochemical defects are clarified and suitable tests become available, electron microscopy remains the only current means for reliable, genetically useful, diagnosis of epidermolysis bullosa. In 62 per cent of cases of our series a prenatal diagnosis of exclusion of disease was made and we would stress that in high risk families repeated fetoscopies for prenatal diagnosis are possible in consecutive pregnancies thus allowing the family to have only normal children.

Epidermolysis Bullosa↗

Beta-thalassemia disease prevention: genetic medicine applied.

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.

Adolescent↗

[Report on 8 years' experience in the prenatal diagnosis of genetic defects. III. Outcome of pregnancy].

The courses of 997 pregnancies out of 1113 prenatal diagnoses were analysed. The total rate of all fetal and neonatal losses is 11.6 per cent inclusively the therapeutically induced abortions. Peculiarities of our material are the shift to higher ages and the inclusion of pregnancies following amniofetography and fetoscopy. Without the last ones the perinatal mortality is 18.9 per thousand, the abortion rate is 2.6 per cent, the rate of premature deliveries (till the 37th gestational week) is 10.2 per cent and the rate of low birth weight babies below 2500 g is 6.1 per cent in connection with a frequency of caesarean sections of 9 per cent. 91 per cent of the newborns had Apgarscore of 8 to 10. The most favourable courses with an abortion rate of 2.2 per cent, a perinatal mortality of 11.8 per cent and a rate of low birth weight babies of 5.7 per cent are to be found following uncomplicated amniocentesis. Perinatal mortality is increased about the factor 10 combined with an threefold raise of prematurity in cases of brownish amniotic fluid. If the amniotic fluid was bloody and the repeated insertions during amniocentesis abortion rate is 10 per cent and perinatal mortality 44.4 per thousand. --3.2 per cent of pregnancies after fetoscopy are terminated by abortions. Perinatal mortality is 33.3 per thousand, the rate of low birth weight babies 26.7 per cent. Pregnancies following amniofetography have a most unfavourable course. The abortion rate is elevated to 11.2 per cent, perinatal mortality to 139.2 per thousand with a rate of low birth weight babies of 41.8 per cent. Following amniofetography every fourth newborn has a birth weight below 1500 grams.(ABSTRACT TRUNCATED AT 250 WORDS)

Abortion, Induced↗

Prenatal detection of epidermolysis bullosa letalis with pyloric atresia in a fetus by abnormal ultrasound and elevated alpha-fetoprotein.

We report on the prenatal diagnosis of epidermolysis bullosa letalis with pyloric atresia in a pregnancy not known to be at risk for this condition. Elevated maternal serum alpha-fetoprotein levels led to ultrasonography which demonstrated gastric dilatation, consistent with pyloric atresia, and echogenic particles in the amniotic fluid, the "snowflake sign," previously described in two pregnancies of fetuses with disorders of skin sloughing. Amniotic fluid alpha-fetoprotein was markedly elevated and the acetylcholinesterase was positive. The diagnosis of epidermolysis bullosa letalis with pyloric atresia was confirmed after delivery by electron microscopy of fetal skin which showed typical changes of hypoplastic absent hemidesmosomes and separation along the dermal-epidermal junction. None of these abnormal prenatal findings are consistently present in pregnancies with epidermolysis bullosa with pyloric atresia. Thus, although useful when abnormal, when the test results are normal, the need for confirmatory fetoscopy and fetal skin biopsy remains.

Abnormalities, Multiple↗

Increased first trimester nuchal translucency as a prenatal manifestation of Smith-Lemli-Opitz syndrome.

Routine ultrasound examination at 11 weeks of gestation in a woman with no family history of genetic disease demonstrated increased accumulation of fluid in the fetal nuchal region. In view of the association of this defect with chromosomal abnormalities, fetal karyotyping was performed by chorion villus sampling and this demonstrated a normal 46,XY karyotype. Subsequent scans showed resolution of the nuchal fluid, and at the 20-week scan the fetal genitalia appeared to be female. Fetal blood sampling confirmed a normal male karyotype and fetoscopy confirmed the presence of female external genitalia. The parents elected to terminate the pregnancy, and postmortem findings were indicative of Smith-Lemli-Opitz syndrome. This was confirmed by the finding of increased levels of 7-dehydrocholesterol in cultured skin fibroblasts.

Adult↗

Apolipoproteins in human fetal blood and amniotic fluid in mid-trimester pregnancy.

To examine the potential for prenatal diagnosis of genetic lipoprotein metabolic defects (e.g. abetalipoproteinemia. Tangier disease) we determined the normal concentrations of apolipoproteins (apo) A-I, A-II, B, and E in mid-trimester amniotic fluid and fetal plasma. The concentrations of apo A-I and apo A-II in amniotic fluid were 1--2 per cent of the respective levels in the mother's plasma, whereas apo B and apo E were undetectable in amniotic fluid. In contrast to amniotic fluid, all four apolipoproteins were detectable in fetal plasma, and the levels of apo A-I, apo B and apo E were in the range observed in the mothers: 160.2 +/- 103.1, 59.8 +/- 35.7 and 5.7 +/- 3.5 mg/dl respectively (mean +/- SD, n = 13). The fetal plasma level of apo A-II (28.3 +/- 12.4 mg/dl) was two-thirds that observed in the mother's plasma. The normal levels of these apolipoproteins in fetal plasma are well above the sensitivity of the methods, and their quantification requires only 10--20 microliters of fetal plasma. Determination of apolipoproteins in fetal blood obtained by fetoscopy thus may provide a method for the prenatal diagnosis of congenital apolipoprotein deficiencies.

Adult↗

The possibility of prenatal diagnosis by gene dosage: confirmation of duplication 10q24 to qter from GOT-1 activity in fetal erythrocytes.

The activity of four enzymes, including GOT-1, has been investigated in he erythrocytes of a 10q to 24 qter trisomic fetus. Analyses have been performed on a feto-maternal blood mixture sampled by fetoscopy and on red cells obtained by cardiac puncture, following therapeutic abortion. The demonstration of a 40 per cent increase of GOT-1 activity, as compared to normal fetuses of similar gestational age, suggests that gene dosage studies may be a useful confirmatory technique in prenatal diagnosis of unbalanced chromosomal aberrations. Practical application of a similar diagnostic approach is conditioned by (1) precise characterization of fetal chromosome imbalance; (2) confirmed assignment of the gene locus coding for the gene product under investigation; (3) evidence of a linear proportionality between gene dose and concentration of the gene product in patients with the same chromosome imbalance detected in the fetus; (4) knowledge of the range of normal variation at different weeks of gestation of the enzyme activity to be tested in the fetus; (5) safety of fetal sampling procedure.

Adult↗

Selective feticide of the affected twin by fetoscopic air embolism.

Three twin pregnancies, each with one affected fetus (by microcephaly, haemophilia A and spina bifida respectively) were encountered. Selective feticide was performed at the patient's request by injection of filtered air into an umbilical vessel by fetoscopy. The method was successful in all three pregnancies two of which resulted in a live, healthy baby.

Abortion, Induced↗