1/45. Intrachromosomal triplication of 2q11.2-q21 in a severely malformed infant: case report and review of triplications and their possible mechanism.A female fetus with brain malformations, multicystic kidneys, absence of the right thumb, and a posterior cleft of palate was delivered at 32 weeks of gestation. Cytogenetic studies including FISH showed a novel intrachromosomal triplication of the proximal long arm of chromosome 2 (q11.2-q21), resulting in tetrasomy for this segment. The middle repeat was inverted. At least 11 patients with intrachromosomal triplications have been reported, mostly involving chromosome 15q. The mechanism involved in formation of these rearrangements is compatible with U-type exchange events among three chromatids.- - - - - - - - - - ranking = 1keywords = gestation (Clic here for more details about this article) |
2/45. sex chromosome pentasomy (49,XXXXY) presenting as cystic hygroma at 16 weeks' gestation.The pentasomy 49,XXXXY is one of the rarest sex chromosome defects, occurring with an estimated incidence of 1 in 85 000 male births. This condition is associated with pre- and postnatal growth deficiency, severe mental retardation, hypogenitalism, and other skeletal, facial and cardio-vascular anomalies. In this report we present such a case diagnosed prenatally by chorionic villus sampling after the ultrasound detection of cystic hygroma at 16 weeks' gestation. Although the prenatal diagnosis of cystic hygroma and its association with aneuploidy has been documented in numerous reports, sex chromosome aneuploidy, other than the 45,X karyotype, accounts for only 0.3 per cent of cases.- - - - - - - - - - ranking = 5keywords = gestation (Clic here for more details about this article) |
3/45. trisomy 2 in an acardiac twin in a triplet in-vitro fertilization pregnancy.A case is reported of twin reversed arterial perfusion (TRAP) sequence in a triamniotic dichorionic triplet pregnancy conceived by in-vitro fertilization which was diagnosed at 25 weeks of gestation by colour Doppler sonography. It highlights the risk of monochorionicity-associated morbidity in multiple pregnancies obtained by assisted conception and stresses the importance of chorionicity determination by early ultrasound examination. cytogenetic analysis of skin from the acardius showed trisomy 2 in all cells, whereas the karyotype in the monochorionic triplet was normal. This is an example of heterokaryotypic monozygotism where the chromosomal abnormality must have occurred during the early cleavage divisions. aneuploidy as a possible aetiological factor of TRAP sequence is discussed.- - - - - - - - - - ranking = 4.3533021988672keywords = gestation, pregnancy (Clic here for more details about this article) |
4/45. Mosaic trisomy 17 in amniocytes: phenotypic outcome, tissue distribution, and uniparental disomy studies.mosaicism for trisomy 17 in amniocyte cultures is a rare finding, whilst postnatal cases are exceptional. In order to gain insight into the possible effects of the distribution of the trisomic line and of uniparental disomy (UPD) on embryofoetal development, we have performed follow-up clinical, cytogenetic and molecular investigations into three newly detected prenatal cases of trisomy 17 mosaicism identified in cultured amniotic fluid. In the first case, the pregnancy ended normally with the birth of a healthy girl, and analysis of newborn lymphocytes and of multiple extra-embryonic tissues was indicative of confined placental mosaicism. The second case was also associated with a normal pregnancy outcome and postnatal development, and only euploid cells were found in peripheral blood after birth. However, maternal isodisomy 17 consequent to a meiosis II error and loss of a chromosome 17 homologue was detected in peripheral lymphocytes postnatally. In the third case, pathological examination after termination of pregnancy showed growth retardation and minor dysmorphisms, and the trisomic line was detected in foetal skin fibroblasts. In addition, biparental derivation of chromosome 17 was demonstrated in the euploid lineage. These results, together with previously reported data, indicate that true amniotic trisomy 17 mosaicism is more commonly of extra-embryonic origin and associated with normal foetal development. Phenotypic consequences may arise when the trisomic line is present in foetal tissues. Case 2 also represents the first observation of maternal UPD involving chromosome 17; the absence of phenotypic anomalies in the child suggests that chromosome 17 is not likely to be subject to imprinting in maternal gametes.- - - - - - - - - - ranking = 2.0119813193203keywords = pregnancy (Clic here for more details about this article) |
5/45. Ontogeny of isolated ultrasound markers for fetal aneuploidy.OBJECTIVE: To evaluate the natural history of isolated ultrasound markers for fetal aneuploidy observed at 14-16 weeks of affected gestations. STUDY DESIGN: 76 aneuploid gestations were diagnosed among a predominantly low-risk population undergoing targeted ultrasonography in the early second trimester. Indications for evaluation of fetal karyotype included fetal malformations or sonographic markers for aneuploidy, maternal age over 35 years and abnormal serum screening results. Markers were re-evaluated at the time of amniocentesis or at pregnancy termination for fetal anomalies. RESULTS: Sonographic markers for aneuploidy (SMA) were observed in 68 of 76 aneuploid gestations diagnosed in the study group. In 46 cases, SMA were associated with major fetal malformations and in 22 cases, markers were isolated. Only 2 of 22 isolated markers for aneuploidy were documented at the time of amniocentesis. CONCLUSION: Isolated ultrasound markers for aneuploidy are transient and may disappear later on in gestation. Transvaginal sonography at 14-16 weeks of gestation appears to provide the best time window for detection of markers for fetal abnormal karyotype.- - - - - - - - - - ranking = 5.6706604397734keywords = gestation, pregnancy (Clic here for more details about this article) |
6/45. Non-invasive exclusion of fetal aneuploidy in an at-risk couple with a balanced translocation.A pregnant woman who was a carrier for a balanced chromosome translocation [46,XX, t(1;6) (p31;q14)] and who had had six miscarriages, declined invasive testing but agreed to non-invasive prenatal diagnosis by analysis of fetal cells in maternal blood. Monoclonal antibody (Mab) against the zeta (z) and gamma (gamma) chains of embryonic and fetal haemoglobin were used to identify fetal nucleated erythrocytes (FNRBC). There were no FNRBC detected at 7 weeks, one anti-z-positive FNRBC was detected at 11 weeks, and 12 anti-gamma-positive FNRBC were detected at 20 weeks. Fluorescent in-situ hybridization was performed using probes for chromosomes X, Y, 1 and 6 to identify fetal gender and the presence of an unbalanced chromosomal translocation. A tentative prenatal diagnosis was made of a female fetus disomic for chromosomes 1 and 6. A female infant with a 46,XX karyotype was born at term. This is the first attempt of exclusion of a chromosome translocation using fetal cells isolated from maternal blood. There is an advantage of using fetal cells isolated from maternal blood for non-invasive prenatal diagnosis in couples who have a history of multiple miscarriages due to a parental translocation, and who decline invasive testing in a pregnancy that continues to the second trimester.- - - - - - - - - - ranking = 0.67066043977343keywords = pregnancy (Clic here for more details about this article) |
7/45. interphase FISH with chromosome-specific protelomere probes for rapid prenatal diagnosis in a reciprocal translocation carrier.interphase fluorescence in situ hybridization (FISH) analysis has become an accepted practice for rapid preliminary analysis of chromosome aneuploidy from direct amniocyte preparations. The use of dual-color interphase FISH analysis with chromosome-specific protelomere probes for the rapid exclusion of chromosomally unbalanced segregants in the pregnancy of a reciprocal translocation carrier is reported. amniocentesis was performed at 16 weeks gestation on the carrier of a t(5;14)(p14.2;p13), who was ascertained after the birth of a son with the der(5) chromosome. interphase FISH analysis with probes for 5pter, 5qter and 14qter showed two signals for each, consistent with alternate segregation of the maternal translocation. Subsequent metaphase analysis confirmed a 46,XY,t(5;14)(p14.2;p13)mat karyotype in the fetus. This case illustrates the utility of interphase FISH analysis with protelomere probes for rapid prenatal diagnosis in cases of parental reciprocal translocation.- - - - - - - - - - ranking = 1.6706604397734keywords = gestation, pregnancy (Clic here for more details about this article) |
8/45. Gastric choriocarcinoma shows characteristics of adenocarcinoma and gestational choriocarcinoma: a comparative genomic hybridization and fluorescence in situ hybridization study.The authors report two cases of the rare primary gastric choriocarcinoma. These tumors showed an overwhelming predominance of cytotrophoblast- and syncytiotrophoblast-like tumor cells that were positive for beta-human chorionic gonadotrophin, with small foci of glandular differentiation. Beta-human chorionic gonadotrophin was also detected serologically in one patient. comparative genomic hybridization study was performed on one specimen. Copy number gains of chromosomes 12, 17, 20, 22, and X, together with losses on 18q, were the major findings. Except for the gain of chromosome 12, which is known to be uncommon in primary gastric adenocarcinoma but frequently associated with choriocarcinoma, the remaining genomic imbalances were among the most common comparative genomic hybridization findings reported in primary gastric adenocarcinoma. fluorescence in situ hybridization on paraffin sections of both specimens confirmed the presence of polysomy 17 and trisomy 12. These results suggest that primary gastric choriocarcinoma genetically possesses characteristics of both adenocarcinoma and gestational choriocarcinoma. The authors believe this is the first interphase cytogenetics study on this rare tumor, and that the results support the theory that gastric choriocarcinoma arises from alternate differentiation pathways of adenocarcinoma.- - - - - - - - - - ranking = 5keywords = gestation (Clic here for more details about this article) |
9/45. Preimplantation genetic diagnosis of pericentric inversions.Inversions are structural chromosome abnormalities that may be associated with infertility, multiple miscarriage and chromosomally unbalanced offspring. Preimplantation genetic diagnosis (PGD) with subtelomeric probes was used to select for transfer only those embryos that were normal or balanced for three pericentric inversions. In contrast to previous protocols the present procedure allows the detection of unbalanced embryos that might arise from U-recombination in the inverted region. Additionally, aneuploidy screening was carried out in two cases by a second round of fluorescent in situ hybridization (FISH) with centromeric probes. Of the three couples that underwent the procedure one became pregnant twice. The first pregnancy delivered a healthy and chromosomally normal baby and the second pregnancy is ongoing with triplets.- - - - - - - - - - ranking = 1.3413208795469keywords = pregnancy (Clic here for more details about this article) |
10/45. Selective termination of aneuploidy utilizing rapid fluorescence in situ hybridization detection techniques.Twin pregnancy following assisted reproductive technology with a euploid fetus and a coexisting aneuploid co-twin constitutes a conflicting situation; therefore, it is important for the genetic constitution of each co-twin to be diagnosed accurately and promptly for parental genetic counseling and subsequent aggressive management. A 35-year-old woman, gravida 1, with a 2-year history of infertility, presented bilateral fallopian tubal obstruction at her infertility workups, for which she received in vitro fertilization; subsequently she conceived a twin pregnancy. She underwent genetic amniocentesis at 16 weeks' gestation, as indicated by an advanced maternal age. Presented with the diagnosis of twin pregnancy with discordancy for trisomy 21, a rapid fluorescence in situ hybridization (FISH) technique for aneuploidy mapping was applied for subsequent abdominal selective fetal reduction. The FISH technique facilitates the rapid analysis of uncultured amniocytes. Normal (disomic) and trisomic samples can be distinguished clearly and rapidly for subsequent selective fetocide. The FISH technique is an important tool in prenatal diagnosis and clinical applications.- - - - - - - - - - ranking = 3.0119813193203keywords = gestation, pregnancy (Clic here for more details about this article) |
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