Evaluation of cardiac findings using speckle tracking in fetuses with hemoglobin Bart's disease.

OBJECTIVE: Hemoglobin (Hb) Bart's disease is a severe manifestation of alpha thalassemia, resulting in fetal tissue hypoxia and severe anemia. There is limited research available on assessing fetal speckle tracking analysis as a response to fetal anemia caused by Hb Bart's disease and its utility as a sonographic predictor for Hb Bart's disease. This study aimed to assess the diagnostic performance of fetal cardiac parameters derived from speckle tracking echocardiography for distinguishing between affected and unaffected fetuses in pregnancies at risk of Hb Bart's disease during the 17-24 gestational weeks. METHODS: A total of 115 pregnant women at risk for fetal Hb Bart's disease, who underwent either amniocentesis or cordocentesis at Siriraj Hospital, Bangkok Thailand, were included. Speckle tracking analysis was performed on the 4-chamber view (4CV) of the fetal heart, assessing heart size, shape, ventricular contractility, and left ventricular function prior to invasive prenatal testing. Logistic regression analysis determined significant cardiac predictors and calculated the probability of a fetus having Hb Bart's disease. RESULTS: Among the cohort, 38 fetuses (33%) were diagnosed with Hb Bart's disease, and 9 cases (7.8%) exhibited frank hydropic signs. In comparison to the control group, affected fetuses displayed a notable enlargement of the 4CV and a more globular shape specifically in the right ventricular chamber. Additionally, there were significant differences in the left global and longitudinal contractility between affected and unaffected fetuses. However, at mid-gestation, no significant distinctions were observed in terms of transverse contractility and left ventricular function between the two groups. Based on logistic regression analysis, combined cardiac parameters derived from speckle tracking analysis as a function of head circumference, could differentiate non-hydropic fetuses with Hb Bart's disease from unaffected fetuses, achieving a maximum sensitivity of 100%, specificity of 98.7%, and overall accuracy of 99.06%. CONCLUSIONS: Speckle tracking echocardiography has the potential to accurately identify early fetal heart changes in individuals at risk of developing Bart's anemia during the second trimester. This not only offers a novel predictive marker for Hb Bart's disease but also helps address the question of the underlying mechanisms of heart failure associated with anemia. This article is protected by copyright. All rights reserved.

A family at risk of congenital adrenal hyperplasia: a molecular approach for prenatal diagnosis.

The molecular method for prenatal diagnosis in the first trimester was carried out on the second and third pregnancies of a family at risk of congenital adrenal hyperplasia (CAH). The first child, an 8-year-old daughter, was affected. The molecular and cytogenetic prenatal diagnosis on the second pregnancy revealed that the fetus which was a female had been affected. The pregnancy was then terminated. The couple presented with the third pregnancy at 8 weeks' gestation. The same approach revealed that the fetus, a male, was affected. The couple opted for continuation of pregnancy which was on-going at the time of the manuscript preparation. To our knowledge, this is the first family in Thailand who had molecular approach for prenatal diagnosis of CAH. This approach allows early information about the fetal status of the disease and, together with the result of fetal gender, will help early decision making in pregnancy management.

FISH analysis on day 5 post-insemination of human arrested and blastocyst stage embryos.

Preimplantation genetic diagnosis (PGD) is usually performed on cleavage stage embryos on day 3 post-insemination. Fluorescent in situ hybridization (FISH) has revealed four groups of chromosome patterns in embryos at this stage: uniformly normal, uniformly abnormal, mosaic and chaotic. Recently, some in vitro fertilization (IVF) clinics have started to perform blastocyst stage transfer. In blastocysts, conventional karyotyping has shown that all four groups of chromosome patterns are observed. In the present study, embryos were cultured to day 5 and were subject to a two-round multicolour FISH procedure for chromosome analysis to ensure almost every nucleus was examined. Probes for chromosomes X, Y and 18 were used in the first round and those for chromosomes 13 and 21 in the second round. Twenty arrested embryos (274 cells) and 19 blastocyst stage embryos (1272 cells) were analysed. Four arrested embryos and two blastocysts were uniformly diploid. The remaining 33 embryos were mosaic, including 17 blastocysts. Most of the blastocysts had a high proportion of diploid cells while in the arrested embryos, this proportion varied widely. For PGD, this high prevalence of mosaicism persisting to the blastocyst stage may pose problems similar to mosaicism in cleavage stage embryos.

Charts of Thai fetal biometries: 1. Methodology.

A cross-sectional study was conducted in order to construct new reference charts for Thai fetal biometries that are commonly used in obstetric ultrasound practice. We discussed and illustrated a sound appropriate study design and statistical analysis which lead to more valid results. A total of 621 normal pregnant women between 12-41 weeks of gestation and their fetuses were recruited. Each fetus was measured once at a randomly assigned gestational age specifically for the purpose of this study only. Stepwise linear regression technique was used to model the mean and its standard deviation as functions of gestational age. Goodness of fit and normality of the data were checked before the final models were chosen. Reference centiles were derived, taking into account the increasing variation as pregnancy proceeds. We demonstrated the stated technique with humerus data from the same study. Reference charts for other fetal biometries have been derived and are presented in subsequent papers.

Examination of trisomy 13, 18 and 21 foetal tissues at different gestational ages using FISH.

In man high levels of aneuploidy are seen in spontaneous abortions. Very few autosomal trisomies survive to birth, the three most common being those for chromosome 13, 18 and 21 giving rise to the syndromes named Patau, Edwards and Down respectively. Since the majority of these spontaneously abort, what makes the survivors different from the aborters? Could it be that they have tissue specific mosaicism with the additional normal cell line supporting survival? In this study fluorescence in situ hybridisation was used as a convenient way to detect trisomy in interphase cells. To study the level of mosaicism across gestation, different tissues from 21 trisomic foetuses were analysed using probes for chromosome 13, 18, 21, X and Y. Two trisomy 18 foetuses exhibited mosaicism. Two others, one trisomy 13 and one trisomy 18 had mosaic placentas. There was no clear association between the limited mosaicism seen and severity of the phenotype. We conclude that at least for this sample set, tissue-specific mosaicism was not likely to be responsible for potential survival to birth.

Relative efficiency of FISH on metaphase and interphase nuclei from non-mosaic trisomic or triploid fibroblast cultures.

Chromosome specific probes that are used in interphase fluorescence in situ hybridization (FISH) analysis are usually tested on disomic control samples. When used for preimplantation or prenatal diagnosis the aim is to detect aneuploidy, most frequently trisomy. In this study, skin fibroblast cultures from non-mosaic trisomic and triploid fetuses were analysed by FISH to assess probe efficiency regarding interphase detection of trisomy. Skin fibroblast cultures were used because they are considered to be stable in culture. FISH experiments were performed using centromeric probes for chromosomes X, Y, 18 and locus specific probes for chromosomes 13 and 21. In metaphase nuclei, the expected signals were found in 100% of at least 30 metaphases counted on each sample and this also confirmed non-mosaicism in agreement with conventional karyotyping of the fetuses. On interphase nuclei, however, only 80-89% of nuclei per population displayed the expected signals for autosomal probes and 90% for probes for the sex chromosomes. For each probe, a range of percentages was obtained that can be regarded as indicative of non-mosaic trisomy in uncultured specimens. In the case of prenatal samples, the expected presence of maternal cells may lead to a lowering of the threshold for a trisomic diagnosis. In the case of preimplantation diagnosis, the accuracy can be improved by the use of two probes per chromosome or by the analysis of two cells from each embryo.