1/17. Analysis of segregation and aneuploidy in two reciprocal translocation carriers, t(3;9)(q26.2;q32) and t(3;9)(p25;q32), by triple-color fluorescence in situ hybridization.Meiotic segregation patterns of chromosomes 3 and 9 were analyzed in sperm of two translocation carriers (t(3;9)(q26.2;q32) and t(3;9)(p25;q32)) by triple-color fluorescent in situ hybridization (FISH) with a telomeric dna probe in addition to two centromeric probes. The frequencies of each sperm product resulting from alternate or adjacent I, adjacent II and 3:1 segregation in a t(3;9)(q26.2;q32) translocation carrier were 88.35%, 5.44% and 5.94%, respectively. On the other hand, the frequencies of each sperm product in a t(3;9)(p25;q32) translocation carrier were 89.23%, 6.02% and 4.48%, respectively. Of all the sperm products, the frequency of normal or chromosomally balanced sperm in a t(3;9)(q26.2;q32) and a t(3;9)(p25;q32) were 52.49% and 47.25%, respectively. The frequencies of each sperm product resulting from various segregations were different between both carriers and significantly deviated from the expected frequencies. Additional dual-color and triple-color FISH were performed to analyze aneuploidy rates for chromosomes 12, 17, 18, X and Y in order to detect any interchromosomal effect; no evidence of an interchromosomal effect was found.- - - - - - - - - - ranking = 1keywords = hybridization (Clic here for more details about this article) |
2/17. 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 = 0.2keywords = hybridization (Clic here for more details about this article) |
3/17. A de novo complex chromosomal rearrangement with a translocation 7;9 and 8q insertion in a male carrier with no infertility.A de novo complex chromosomal rearrangement (CCR) involving chromosomes 7, 8 and 9 in a male carrier was ascertained through his healthy wife's recurrent spontaneous abortions. Six pregnancies over eight years resulted in four spontaneous abortions and two livebirths who died perinatally due to abnormal vital signs. Cytogenetic analyses utilizing high resolution chromosome banding technique showed a deletion of band in a der(7) chromosome and an extra band inserting at 8q21.2. Another extra band was also observed at the band 9p24, but it could not be karyotypically determined. Fluorescent in-situ hybridization using chromosome 7 and 8 specific microdissected library as probes confirmed the insertion of a segment from the translocated chromosome 7 into a chromosome 8, and additionally revealed a translocation between chromosomes 7 and 9. The karyotype of the CCR carrier was determined as 46,XY,t(7;9)(q22;p24),ins(8;7)(q21.2;q22q32).ish der(9)(wcp7 );ins(8;7)(wcp8 ,wcp7 ). Comparing with previously reported male CCR carriers with our case, we conclude that male CCR carriers may not always present with infertility or subfertility phenotypes. This may suggest that rare transmission of male carriers could result from abnormal chromosomal rearrangements during meiosis and gametogenesis in addition to frequent infertility.- - - - - - - - - - ranking = 0.2keywords = hybridization (Clic here for more details about this article) |
4/17. A case with balanced chromosome rearrangement involving chromosomes 9, 14, and 13 in a woman with recurrent abortion.A phenotypically normal couple was referred for cytogenetic evaluation due to three consecutive first-trimester spontaneous abortions. Chromosomal analysis from peripheral blood was performed according to standard cytogenetic methods using G-banding technique. The husband's karyotype was normal. The wife's karyotype showed a balanced complex chromosome rearrangement (CCR) involving chromosomes 9, 14, and 13. There were three breakpoints: 9p21.2, 14q21, and 13q12.2. The karyotype was designated as 46, XX, t (9;14;13)(p21.2;q21;q12.2). fluorescence in situ hybridization (FISH) analysis with chromosome-specific libraries of chromosomes 9, 14, and 13 was performed to confirm this rare chromosome rearrangement. The result of FISH coincided with that obtained by standard cytogenetic techniques.- - - - - - - - - - ranking = 0.2keywords = hybridization (Clic here for more details about this article) |
5/17. Multicolour spectral karyotyping for complex chromosomal rearrangements in repeated abortion or congenital anomalies.Advances in molecular cytogenetics, especially the technique of fluorescence in situ hybridization (FISH), have allowed more precise definition of chromosomal structures, which are difficult to identify using conventional G-banding. Recently, a novel approach based on hybridization of 24 fluorescent-labelled chromosome painting probes was developed, termed spectral karyotyping (SKY), which allows the simultaneous and differential colour display of all human chromosomes. We have used SKY to identify not only five parental complex translocation carriers but also minute chromosome rearrangements in the fetus. Here, we concentrate attention on the clinical application of SKY for prenatal diagnosis.- - - - - - - - - - ranking = 0.4keywords = hybridization (Clic here for more details about this article) |
6/17. prenatal diagnosis of a familial complex chromosomal rearrangement involving chromosomes 5, 10, 16 and 18.We report one case of a familial complex chromosomal rearrangement (CCR) involving four different chromosomes 5, 10, 16 and 18. The CCR was detected prenatally at 20 weeks' gestation because of advanced maternal age and history of recurrent miscarriages. cytogenetic analysis of cultured amniotic fluid cells with GTG banding showed a 46,XX,t(5;16;10;18)(q13;q22;q11.2;q21) karyotype. Parental cytogenetic study revealed that the mother has the same CCR. RBG banding, high resolution banding and fluorescence in situ hybridization (FISH) were used to characterize further and confirm the conventional banding data. No physical abnormalities were shown in the targeted fetal ultrasonography examination. The parents decided to continue the pregnancy. The child is now 2 years old and has neither congenital anomalies nor evidence of delayed psychomotor development. The fetal targeted ultrasound and FISH analysis helped us reassure fetal status.- - - - - - - - - - ranking = 0.2keywords = hybridization (Clic here for more details about this article) |
7/17. Unexpected retention and concomitant loss of subtelomeric regions in balanced chromosome anomalies by FISH.Florescence in situ hybridization (FISH) using subtelomeric probes has been useful in detecting cryptic telomeric chromosomal rearrangements. We report, for the first time, that cytogenetically visible chromosome rearrangements can occur between the subtelomeric and telomeric region in clinically normal individuals with balanced chromosome anomalies in which one of the breakpoints involves a terminal band region. Using FISH with subtelomeric probes, we observed in three cases with a balanced reciprocal translocations the retention and subsequent loss of subtelomeric regions. In one case with a paracentric inversion, there was a proximal relocation of a subtelomeric region. Because subtelomeric regions serve important roles in chromosome pairing, this retention and concomitant loss or relocation of a subtelomeric region could possibly further disrupt the complex meiotic configurations of these balanced chromosome rearrangements. This may then have an effect on gamete production, placing these individuals at a higher risk for miscarriages and/or abnormal outcomes for individuals with similar chromosome aberrations.- - - - - - - - - - ranking = 0.2keywords = hybridization (Clic here for more details about this article) |
8/17. Familial cryptic translocation (2;17) ascertained through recurrent spontaneous abortions.We report a young woman who presented with a reproductive history of three recurrent spontaneous abortions (RSA) and two neonatal deaths. comparative genomic hybridization (CGH) was used to determine the chromosomal composition of the patient's last miscarriage. It showed the presence of monosomy for the distal end of chromosome 2 long arm (segment 2q37.2 to qter) and trisomy for the distal end of chromosome 17 long arm (segment 17q25 to qter). The mother was found to be a carrier for a cryptic translocation between chromosomes 2 and 17 long arms by fluorescence in situ hybridization using a subtelomeric probe for 17q. Retrospective CGH analysis on one baby who died neonatally showed that he had inherited the maternal translocation in the same unbalanced state as the last pregnancy loss. His detailed postmortem examination is reported.- - - - - - - - - - ranking = 0.4keywords = hybridization (Clic here for more details about this article) |
9/17. Preimplantation genetic diagnosis for a couple with recurrent pregnancy loss and triploidy.BACKGROUND: triploidy may arise from fertilization of a mature haploid egg by two haploid sperm or by failure of meiotic divisions yielding a diploid gamete. We encountered a couple with habitual abortion, in which the last two fetuses were documented as viable triploid. methods: To avoid dispermic penetration and development of abnormal preembryos, insemination was done by intracytoplasmic sperm injection (ICSI) followed by fluorescence in situ hybridization (FISH) of biopsied blastomeres. RESULTS: Tests of the husband's spermatozoa by FISH, revealed that only 2-3% of the sperm were disomic for chromosomes 16, 13, 21, X, and Y. No triple disomy was detected among chromosomes 16, 13 and 21, which makes it very unlikely that triploidy resulted from diploid spermatozoa. Following a controlled ovulation induction protocol, low quality oocytes with immature cumuli were revealed. After ICSI, five eggs became two pronuclei (2PN) zygotes and none of the other eggs developed a 3PN zygote. FISH was performed on chromosomes 16 and 21 in four preembryos developed to a 6-8 cell stage. aneuploidy or mosaicism for each of these chromosomes was detected in one preembryo and later in two disaggregated blastocysts. FISH failed in one preembryo that became atretic after biopsy. CONCLUSIONS: Although this case was unsuccessful in achieving embryo transfer and normal pregnancy, we detected many abnormal morphological features in the oocytes and chromosomal abnormalities in the cleaving preembryos. This protocol can be proposed to patients with recurrent pregnancy loss associated with chromosomal abnormalities in the fetus.- - - - - - - - - - ranking = 0.2keywords = hybridization (Clic here for more details about this article) |
10/17. Successful pregnancy after preimplantation genetic diagnosis in a female with Robertsonian translocation.Preimplantation genetic diagnosis (PGD) is an alternative option for couples with chromosome abnormalities. A 34-year-old woman with balanced Robertsonian translocation [(45, XX, der(13; 14)(q10; q10)] requested PGD due to recurrent spontaneous abortion. Embryos of good quality were biopsied on day 3 post-oocyte retrieval. The aspirated blastomeres were fixed and analyzed using fluorescence in situ hybridization. In the first cycle, 2 unaffected embryos were transferred back without success. No unaffected embryo was available in the second cycle. On day 5 in the third cycle, 2 unaffected embryos were transferred resulting in a twin pregnancy. amniocentesis confirmed the diagnosis. At the gestational age of 35 weeks, 2 healthy girls were born via cesarean section. Postnatal physical examination found no evidence of major abnormalities.- - - - - - - - - - ranking = 0.2keywords = hybridization (Clic here for more details about this article) |
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