1/18. Male infertility associated with a unique 8;22 translocation.Proper evaluation of male infertility includes a careful history, physical examination, semen analysis, and karyotyping. Molecular cytogenetic analysis may also be necessary to further delineate the karyotype. Following the above approach, we found an apparently unique 8;22 translocation in a male patient with infertility but few other phenotypic manifestations. Delineating the exact genetic basis of infertility is important in view of the most recent advances in reproductive technology such as in vitro fertilization and intracytoplasmic sperm injection. patients utilizing these emerging techniques need to be properly counseled as to their risks of transmitting these chromosomal abnormalities to their offspring.- - - - - - - - - - ranking = 1keywords = fertilization (Clic here for more details about this article) |
2/18. Molecular cloning of translocation breakpoints in a case of constitutional translocation t(11;22)(q23;q11) and preparation of probes for preimplantation genetic diagnosis.in vitro fertilization (IVF) centres with preimplantation genetic diagnosis (PGD) programmes are often confronted with the problem of identifying chromosomal abnormalities in interphase cells biopsied from preimplantation embryos of carriers of a reciprocal translocation. The present authors have developed a DNA testing based approach to analyse embryos from translocation carriers, and this report describes breakpoint-spanning probes to detect abnormalities in cases of the most common human translocation (i.e. the t(11;22)(q23;q11)). Screening a yeast artificial chromosome (YAC) library for probes covering the respective breakpoint regions in the patient lead to probes for the breakpoint on chromosome 11q23. The physically mapped YAC and bacterial artificial chromosome (BAC) clones from chromosome 22 were then integrated with the cytogenetic map, which allowed localization of the breakpoint on chromosome 22q11 to an interval of less than 84 kb between markers D22S184 and KI457 and to prepare probes suitable for interphase cell analysis. In summary, breakpoint localization could be accomplished in about 4 weeks with additional time needed to optimize probes for use in PGD.- - - - - - - - - - ranking = 1keywords = fertilization (Clic here for more details about this article) |
3/18. Preimplantation genetic diagnosis of a reciprocal translocation t(3;11)(q27.3;q24.3) in siblings.Preimplantation genetic diagnosis (PGD) was performed in two couples to avoid chromosomally unbalanced progeny in a family in which a brother and a sister carry an identical maternally inherited balanced translocation t(3;11)(q27.3;q24.3). Embryos were biopsied 3 days after fertilization and blastomeres were analysed by fluorescent in-situ hybridization (FISH). Embryos were classified as unbalanced or normal/balanced. In the first case, the male carrier and his wife underwent one IVF/PGD treatment cycle. In all, 18 embryos were analysed. Of those, 15 revealed an unbalanced karyotype. For one embryo, results were not conclusive, from one embryo results were contradictory and one embryo was classified as normal/balanced and subsequently transferred. A singleton pregnancy was achieved. The PGD analysis was confirmed at 16 weeks gestation by amniocentesis. At term, a healthy girl with a balanced karyotype was born. pregnancy and delivery were without complications. In the second case, the female carrier and her husband underwent two IVF/PGD treatment cycles. During the first cycle, three embryos were analysed. One embryo revealed an unbalanced karyotype and two embryos were designated a normal/balanced karyotype and transferred but no pregnancy was achieved. During the second PGD cycle three embryos were analysed. Of those, none appeared suitable for transfer. The couple decided not to undergo further treatment. Our results indicate that for individuals carrying a reciprocal translocation PGD is a feasible approach to obtain embryos with a normal chromosome balance and to avoid both spontaneous and induced abortion.- - - - - - - - - - ranking = 1keywords = fertilization (Clic here for more details about this article) |
4/18. Case-specific, breakpoint-spanning dna probes for analysis of single interphase cells.Balanced reciprocal translocations are known to interfere with homolog pairing in meiosis. Many individuals carrying such chromosomal abnormalities suffer from reduced fertility or spontaneous abortions and seek help in the form of assisted reproductive technology. Although most translocations are relatively easy to detect in metaphase cells, the majority of embryonic cells biopsied in the course of in vitro fertilization (IVF) procedures are in interphase. These nuclei are, thus, unsuitable for analysis by chromosome banding or painting using fluorescence in situ hybridization (FISH). Our assay, based on FISH detection of breakpoint-spanning dna probes, identifies translocations in interphase nuclei by microscopic inspection of hybridization domains. Probes are selected that span the breakpoint regions on normal homologs. The probes should hybridize to several hundred kilobases of DNA flanking the breakpoint. The two breakpoint-spanning dna probes for the translocation chromosomes are labeled in separate colors (e.g., red and green). The translocation event producing two fused red/green hybridization domains can then be detected in interphase cell nuclei using a fluorescence microscope. We applied this scheme to analyze somatic and germ cells from 21 translocation patients, each with distinct breakpoints. Here, we summarize our experience and provide a description of strategies, cost estimates, as well as typical time frames.- - - - - - - - - - ranking = 1keywords = fertilization (Clic here for more details about this article) |
5/18. in vitro fertilization and blastocyst transfer for carriers of chromosomal translocation.blastocyst transfers (BT), may benefit chromosomal translocation-carrier couples who suffer multiple miscarriages or are unable to achieve pregnancy following classical art techniques. in vitro culture applies an additional selection pressure, so that those embryos which achieve blastocyst formation have higher survival probability as healthy balanced translocation carriers or unaffected embryos.Sixteen IVF cycles were performed in 11 patients. When blastocyst are obtained, implantation rate per blastocyst and delivery rates (7/11 cycles, eight healthy babies born) are high. However, the overall blastocyst formation rate is low (20%), and as a consequence in nearly half of the cycles, no blastocyst can be obtained. We propose that this strategy may be used initially as an alternative or a complement to preimplantation genetic diagnosis, and to apply the forces of natural selection in vitro.- - - - - - - - - - ranking = 4keywords = fertilization (Clic here for more details about this article) |
6/18. First reported convergence of premature ovarian failure and cutis marmorata telangiectatica congenita.OBJECTIVE: To describe the convergence of five rare phenotypic features in a woman with premature ovarian failure referred for reproductive endocrinology evaluation.DESIGN: Case report and literature review. SETTING: Major urban infertility referral center. PATIENT(S): A 24-year-old nulligravida with cutis marmorata telangiectatica congenita (CMTC), premature ovarian failure, unilateral ovarian agenesis, septate uterus, and de novo balanced autosomal translocation. INTERVENTION(S): High-resolution chromosomal evaluation, radiographic study of reproductive organs, and assessment of endogenous estrogen production. MAIN OUTCOME MEASURE: Patient counseling regarding future reproductive options (i.e., donor oocyte in vitro fertilization/embryo transfer), and satisfactory management of hypoestrogenism using oral contraceptives. RESULT(S): We identified a balanced reciprocal translocation 46,XX t(8;9)(q22.1;p24.1), and confirmed unilateral ovarian agenesis with midline intrauterine septum. CONCLUSION(S): Although genetic factors considered contributory to premature ovarian failure usually involve the x chromosome, in our patient a previously undescribed autosomal translocation was identified in association with CMTC, a rare vascular disorder. The fundamental role of follicular oxygenation in oocyte competence and subsequent ovarian function is discussed. From the clinical and laboratory findings evident in this unusual case, a developmental hypothesis connecting the vascular abnormalities of CMTC and premature ovarian failure is offered.- - - - - - - - - - ranking = 1keywords = fertilization (Clic here for more details about this article) |
7/18. mosaicism in a patient with down syndrome reveals post-fertilization formation of a Robertsonian translocation and isochromosome.It has been estimated that a few hundred children are born each year in the united states with translocation down syndrome. About 5% of the cases with down syndrome carry a Robertsonian translocation involving chromosome 21. The case described here is a patient with down syndrome who showed mosaicism for two cell lines. Each cell line contains a different, de novo acrocentric rearrangement. We constructed somatic cell hybrids from the patient's cells and determined the parental origins of the rearrangements by molecular and fluorescence in situ hybridization (FISH) analyses. The analysis showed that the rob(14q21q) formed between a paternally inherited chromosome 21 and a maternally inherited chromosome 14, indicating that this rearrangement formed post-zygotically. Further molecular analysis also determined that the rea(21q21q) is an isochromosome of paternal origin. The cell line containing the isochromosome is unbalanced, resulting in trisomy 21. Because the same paternal chromosome 21 was involved in both the isochromosome and the Robertsonian translocation, we speculate that an unstable chromosome 21 was stabilized either through formation of a rob(14q21q) or through formation of an isochromosome. The mechanism proposed for the formation of the rob(14q21q) in this case is different from that for most de novo rob(14q21q), but similar to a previously reported mosaic case of down syndrome.- - - - - - - - - - ranking = 4keywords = fertilization (Clic here for more details about this article) |
8/18. Prenatal detection of mosaic trisomy 1q due to an unbalanced translocation in one fetus of a twin pregnancy following in vitro fertilization: a postzygotic error.Complete or mosaic trisomy for all of chromosome 1q has been seen rarely in a recognized pregnancy. A patient presented with twins following in vitro fertilization (IVF). Ultrasound showed twin A to have a diaphragmatic hernia, thick nuchal fold, and subtle intracranial abnormalities. Twin B appeared normal and a thick dividing membrane was seen. amniocentesis of twin A showed a male karyotype with mosaic trisomy 1q in 57% of cells resulting from a translocation between chromosomes Yq12 and 1q12. Parental karyotypes were normal. The twins were delivered at 33 weeks. Twin A died at 1 hr of life. autopsy confirmed the left diaphragmatic hernia and hypoplastic lungs. autopsy also revealed a partial cleft palate, syndactyly of the second and third toes bilaterally, external deviation of the left 5th toe, and contractures of the index fingers bilaterally. A recent report documented formation of a chimera resulting from embryo amalgamation after IVF. Given the rarity of the cytogenetic findings in our case, we sought to determine if the mosaicism was a result of chimera formation related to the IVF. Thirteen polymorphic loci throughout the genome, in addition to four on 1q and four on 1p, were amplified by PCR. Only two alleles were observed at each of these loci in twin A, one paternal and the other maternal. We present further clinical findings of this case with a rare cytogenetic abnormality that appears to have originated from a postzygotic mitotic error and not embryo amalgamation.- - - - - - - - - - ranking = 5keywords = fertilization (Clic here for more details about this article) |
9/18. Preimplantation genetic diagnosis for a known cryptic translocation: follow-up clinical report and implication of segregation products.This report describes preimplantation genetic diagnosis (PGD) of a couple with a known paternally-derived balanced cryptic translocation 46,XY.ish t(2q;17q)(210E14-,B37c1 ;B37c1-,210E14 ) in embryos from a couple who previously had a child with severe mental retardation and was previously described in this journal [Bacino et al., 2000]. This child inherited the unbalanced product of translocation from her father: 46,XX.ish der(2)t(2q;17q)pat(210E14-,B37c1 ). The couple desired a normal offspring and sought PGD to avoid clinical pregnancy termination. They were treated three times with in vitro fertilization followed by PGD. Two sequential FISH hybridizations were performed. In the first hybridization, telomeric probes to 2q and 17q and a chromosome 17 centromere probe were employed. The second hybridization screened for maternal age-related aneuploidy (X,Y,13,18,21). Of the 18 informative embryos, only 4 (22%) were normal. The remaining 12 (67%) were abnormal; most with unbalanced products (10/12) from the paternally-derived rearrangement. The most frequent mode of segregation observed for this cryptic translocation was adjacent-1 (7/18, 39%). This suggests cryptic translocations are amenable to PGD and, as are traditional translocations, demonstrate higher frequencies of unbalanced segregants than the empiric risk of 10-15% observed at amniocentesis or chorionic villus sampling. Thus, cryptic translocations presumably behave like overt translocations, in that PGD must be performed on a relatively large number of embryos to assure even 2-3 transferable embryos.- - - - - - - - - - ranking = 1keywords = fertilization (Clic here for more details about this article) |
10/18. Meiotic segregation of a 21;22 Robertsonian translocation.In-vitro fertilization of hamster oocytes with human spermatozoa has been used to study heterozygotes for structural chromosome abnormalities. To date only four men heterozygous for Robertsonian translocations have been examined. In this study, 150 sperm chromosome complements from a 21;22 translocation were investigated. There was no evidence of an interchromosomal effect since the frequency of abnormalities unrelated to the translocation was within the range of normal donors. The frequency of unbalanced complements was 3.4%, which is similar to other Robertsonian translocations. As expected, an equivalent number of normal (n = 74) and balanced (n = 70) karyotypes was observed.- - - - - - - - - - ranking = 1keywords = fertilization (Clic here for more details about this article) |
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