Assisted reproductive technology treatment outcomes

Information on the outcomes of ART treatments in Ireland is not readily available to Irish practitioners. The data for hospital affiliated clinics has been made available for many years and is included in the hospital reports. We present a 10-year analysis of the Irish ART results voluntarily reported by six out of seven IVF clinics. The data was collected from published ESHRE reports and from results (2007-8) not yet published. Data collected included: number of clinics and ART cycles, female age, clinical and multiple pregnancy rates and treatment complications. The clinical pregnancy rate per embryo transfer was 31.7% for IVF and 29.8% for ICSI. The proportion of singleton, twin and triplet deliveries for IVF and ICSI combined was 75%, 23.35% and 1.64%. The rate of ovarian hyperstimulation was 0.8%. ART practice in Ireland is safe, effective and responsible. Financial and societal savings could result from the introduction of state funded IVF with compulsory eSET where recommended.     

Chromothripsis and beyond: rapid genome evolution from complex chromosomal rearrangements

Recent genome sequencing studies have identified several classes of complex genomic rearrangements that appear to be derived from a single catastrophic event. These discoveries identify ways that genomes can be altered in single large jumps rather than by many incremental steps. Here we compare and contrast these phenomena and examine the evidence that they arise “all at once.” We consider the impact of massive chromosomal change for the development of diseases such as cancer and for evolution more generally. Finally, we summarize current models for underlying mechanisms and discuss strategies for testing these models.     

Balanced complex chromosome rearrangements: reproductive aspects. A review

This review examines the reproductive consequences for carriers of a balanced complex chromosome rearrangement (CCR). It is based on an analysis of CCRs in 103 adults referred for reproductive problems, including male infertility. The main focus is on reproductive risks based on data from 84 CCRs. Carriers of balanced CCRs have a high risk of an abortion and/or a chromosomally unbalanced child. I have identified roughly four different types of CCRs (I-IV); most (44%) belong to Type I with a simple 3-way or 4-way exchange of segments and risk factors similar to those for reciprocal translocations. There were only three CCRs (4%) of type II, which involve an inversion. Type III CCRs (21%) involve one or more insertions with ～35% risk of a child with a duplication or a deletion of the inserted segment. Type IV CCRs (31%) involve a "middle segment" in a derivative chromosome with segments from at least three chromosomes. In ～35% of these CCRs, recombination occurs in this segment, which can produce imbalance but in many cases it changes a CCR into a simpler balanced rearrangement in the next generation. Balanced CCRs, which have been often considered together in one group, can now be split into four types, each with a risk of a different type of imbalance. This analysis provides a better understanding of the reproductive consequences for carriers of balanced CCRs and should be useful in prenatal diagnosis and genetic counseling.     

Characterization of complex chromosomal rearrangements by targeted capture and next-generation sequencing

Translocations are a common class of chromosomal aberrations and can cause disease by physically disrupting genes or altering their regulatory environment. Some translocations, apparently balanced at the microscopic level, include deletions, duplications, insertions, or inversions at the molecular level. Traditionally, chromosomal rearrangements have been investigated with a conventional banded karyotype followed by arduous positional cloning projects. More recently, molecular cytogenetic approaches using fluorescence in situ hybridization (FISH), array comparative genomic hybridization (aCGH), or whole-genome SNP genotyping together with molecular methods such as inverse PCR and quantitative PCR have allowed more precise evaluation of the breakpoints. These methods suffer, however, from being experimentally intensive and time-consuming and of less than single base pair resolution. Here we describe targeted breakpoint capture followed by next-generation sequencing (TBCS) as a new approach to the general problem of determining the precise structural characterization of translocation breakpoints and related chromosomal aberrations. We tested this approach in three patients with complex chromosomal translocations: The first had craniofacial abnormalities and an apparently balanced t(2;3)(p15;q12) translocation; the second has cleidocranial dysplasia (OMIM 119600) associated with a t(2;6)(q22;p12.3) translocation and a breakpoint in RUNX2 on chromosome 6p; and the third has acampomelic campomelic dysplasia (OMIM 114290) associated with a t(5;17)(q23.2;q24) translocation, with a breakpoint upstream of SOX9 on chromosome 17q. Preliminary studies indicated complex rearrangements in patients 1 and 3 with a total of 10 predicted breakpoints in the three patients. By using TBCS, we quickly and precisely defined eight of the 10 breakpoints.     

Catastrophic cellular events leading to complex chromosomal rearrangements in the germline

Although complex chromosomal rearrangements were thought to reflect the accumulation of DNA damage over time, recent studies have shown that such rearrangements frequently arise from ‘all‐at‐once’ catastrophic cellular events. These events, designated chromothripsis, chromoanasynthesis, and chromoanagenesis, were first documented in the cancer genome and subsequently observed in the germline. These events likely result from micronucleus‐mediated chromosomal shattering and subsequent random reassembly of DNA fragments, although several other mechanisms have also been proposed. Typically, only one or a few chromosomes of paternal origin are affected per event. These events can produce intrachromosomal deletions, duplications, inversions, and translocations, as well as interchromosomal translocations. Germline complex rearrangements of autosomes often result in developmental delay and dysmorphic features, whereas X chromosomal rearrangements are usually associated with relatively mild clinical manifestations. The concept of these catastrophic events provides novel insights into the etiology of human genomic disorders. This review introduces the molecular characteristics and phenotypic outcomes of catastrophic cellular events in the germline.     

Chromosome microdissection in leukemia: A powerful tool for the analysis of complex chromosomal rearrangements

In many human cancers the presence of marker chromosomes or unbalanced translocations prevents complete karyotypic analysis. Chromosome microdissection has become an increasingly important method for assessing chromosome rearrangements. However, most studies using chromosome microdissection have been carried out on established cancer cell lines that provide an unlimited supply of abnormal metaphase cells. We have routinely performed microdissection of as few as three marker chromosome copies from short-term cultures of acute myeloid leukemias, followed by in vitro DNA amplification and fluorescence in situ hybridization (FISH) to normal metaphase spreads. Using this type of “reverse chromosome painting,” we were able to characterize precisely the chromosomal constitution of each marker chromosome in the samples, confirming the diagnostic usefulness of microdissection in cancer cytogenetics. In addition, in one leukemia with atypical cytological features, microdissection enabled us to detect a novel retinoic acid receptor α gene rearrangement. Genes Chromosom Cancer 15:26–33 (1996). © 1996 Wiley-Liss, Inc.     

Balanced complex chromosomal rearrangements with more than four breakpoints: report of a new case

Congenital complex chromosomal rearrangement (CCR) compatible with life are rare in man. We report on a new case of apparently balanced CCR in a 30-month-old boy with mental retardation and minor anomalies. This CCR consists in a 3-way reciprocal translocation (2;3;16) and an insertion (6;7), as it was analyzed by different banding and high resolution techniques. It involves 6 breakpoints: 2q11, 13q12, 16p11, 6p21.3, 7q21.3 and 7q35.     

Embryo development and chromosomal anomalies after ICSI: effect of the injection procedure

Intracytoplasmic sperm injection (ICSI) is a delicate procedure requiring considerable skills of the person performing it. Theoretically, the injection procedure could damage cytoplasmic structures in the oocyte, resulting in sublethal cellular injury and/or numerical chromosomal abnormalities that could lead to impaired embryonic development. In the present study, features of the injection procedure were evaluated in a total of 2924 oocytes from 305 cycles. Development to the blastocyst stage was found to be compromised in a group of surplus embryos originating from oocytes in which >6 pl of cytoplasm was aspirated into the injection pipette during the ICSI procedure. Characteristics of the injection procedure as well as blastocyst development of surplus embryos was shown to be significantly different between the four technicians performing the ICSI. Neither the volume of cytoplasm aspirated during the injection procedure, nor the position of the polar body (6 o'clock or 12 o'clock) influenced the mean incidence of disomic cells per blastocyst as revealed by fluorescence in-situ hybridization using probes specific for chromosomes X, Y and 18. In conclusion, certain technical aspects of the injection procedure can affect subsequent embryonic development to the blastocyst stage, but do not seem to influence the rate of chromosomal abnormalities that occur in human pre-implantation embryos.     

Assisted reproductive technology and congenital overgrowth: some speculations on a case of Pallister-Killian syndrome

We report on a boy with Pallister-Killian syndrome (PKS) who was conceived by assisted reproductive technology (ART), specifically in vitro fertilization (IVF) with parents' gametes. A prenatal diagnosis performed elsewhere by CVS failed to detect the presence of the isochromosome 12p that was demonstrated postnatally in approximately 50% of cultured skin fibroblasts. Given that the patient did not show the congenital overgrowth typical of PKS, we speculate that ART might have restricted overgrowth in this particular case. More broadly, we hypothesize that overgrowth might protect from early demise fetuses conceived by ART, a technology known to cause low and very low birth weight.     

Primary myelodysplastic syndrome with complex chromosomal rearrangements in a patient with Klinefelter''s syndrome.

A patient with Klinefelter's syndrome and diabetes mellitus was diagnosed as having myelodysplasia. Cytogenetic analysis of the peripheral blood and the bone marrow cells confirmed the presence of a constitutional 47,XXY chromosome complement. In addition, complex karyotypic abnormalities were present.     

Assisted reproductive technology in Europe, 2008: results generated from European registers by ESHRE

BACKGROUND: This 12th European IVF-monitoring (EIM) report presents the results of treatments involving assisted reproductive technology (ART) initiated in Europe during 2008. METHODS: From 36 countries (3 more compared with 2007), 1051 clinics reported 532 260 treatment cycles including: IVF (124 539), ICSI (280 552), frozen embryo replacements (FER, 97 120), egg donation (ED, 13 609), in vitro maturation (IVM, 562), preimplantation genetic diagnosis/screening (PGD/PGS, 2875) and frozen oocyte replacements (FOR, 4080). Overall, this represents a 7.9% increase in the activity since 2007, which is mainly related to an increase in cycles from almost all registers and only partially to the new countries entering EIM (Estonia, Kazakhstan, Moldova and Romania, 5480 cycles in total). European data on intrauterine insemination using husband/partner's (IUI-H) and donor (IUI-D) semen were reported from 27 and 21 countries, respectively. A total of 144 509 IUI-H (+1.5%) and 24 960 IUI-D (-4.3%) cycles were included. RESULTS: In 19 countries where all clinics reported to the ART register, a total of 350 143 ART cycles were performed in a population of 369.8 million, corresponding to 947 cycles per million inhabitants. For IVF, the clinical pregnancy rates per aspiration and per transfer were 28.5 and 32.5%, respectively, and for ICSI the corresponding rates were 28.7 and 31.9%. In FER cycles, the pregnancy rate per thawing was 19.3%. The delivery rate after IUI was 9.1% for IUI-H and 13.8% for IUI-D. In IVF and ICSI cycles, one, two, three and four or more embryos were transferred in 22.4, 53.2, 22.3 and 2.1%, respectively. The proportions of singleton, twin and triplet deliveries after IVF and ICSI (combined) were 78.3, 20.7 and 1.0%, respectively, resulting in a total multiple delivery rate of 21.7%, compared with 22.3% in 2007, 20.8% in 2006 and 21.8% in 2005. In FER cycles, the multiple delivery rate was 13.7% (13.4% twins and 0.3% triplets). In women undergoing IUI, twin and triplet deliveries occurred in 10.6% and 0.7% with IUI-H and in 9.4 and 0.3% with IUI-D, respectively. CONCLUSIONS: In comparison with previous years, there was an increase in the reported number of ART cycles in Europe. For the first time in 5 years, the pregnancy rates failed to show a year-on-year increase. Compared with 2007, the number of transfers of multiple embryos (3+) and a multiple delivery rate showed a marginal decline.     

Assisted reproductive technology in Europe, 2004: results generated from European registers by ESHRE

BACKGROUND: European results of assisted reproductive techniques from treatmentsinitiated during 2004 are presented in this eighth report. METHODS: Data were mainly collected from existing national registers.From 29 countries, 785 clinics reported 367 066 treatment cyclesincluding: IVF (114 672), ICSI (167 192), frozen embryo replacement(FER, 71 997), egg donation (ED, 10 334), preimplantation geneticdiagnosis/screening (PGD/PGS, 2701) and in vitro maturation(IVM, 170). Overall, this represents only a marginal increasesince 2003, due to a huge reduction in treatments in Germany.European data on intrauterine insemination using husband/partner’ssemen (IUI-H) and donor semen (IUI-D) were reported from 20countries. A total of 115 980 cycles (IUI-H, 98 388; IUI-D,17 592) were included. RESULTS: In 14 countries where all clinics reported to the IVF register,a total of 248 937 ART cycles were performed in a populationof 261.6 million, corresponding to 1095 cycles per million inhabitants.For IVF, the clinical pregnancy rates per aspiration and pertransfer were 26.6% and 30.1%, respectively. For ICSI, the correspondingrates were 27.1% and 29.8%. After IUI-H, the clinical pregnancyrate was 12.6% in women below 40. After IVF and ICSI, the distributionof transfer of 1, 2, 3 and 4 or more embryos was 19.2%, 55.3%,22.1% and 3.3%, respectively. Compared with 2003, fewer embryoswere transferred, but huge differences still existed betweencountries. The distribution of singleton, twin and triplet deliveriesafter IVF and ICSI combined was 77.2%, 21.7% and 1.0%, respectively.This gives a total multiple delivery rate of 22.7% comparedwith 23.1% in 2003 and 24.5% in 2002. After IUI-H in women below40 years of age, 11.9% were twin and 1.3% triplet gestations. CONCLUSIONS: Compared with earlier years, the reported number of ART cyclesin Europe increased and the pregnancy rates increased marginally,even though fewer embryos were transferred and the multipledelivery rates were reduced.     

Cryptic and complex chromosomal rearrangements and the deletion of TP53 gene in a patient with leukemic mantle cell lymphoma

We present a case of leukemic mantle cell lymphoma with cryptic and complex chromosomal rearrangements, including multiple-way translocations involving chromosomes 8q24, 14q11/q32, 17p13.3, 17p13.1, 21q22, and 21q22; a deletion of the long arm of chromosome 10 [del(10)(q24)]; and a deletion of the TP53 gene in addition to t(11;14). We speculate that this series of chromosomal changes may disrupt the IgH gene, activate the c-MYC oncogene, inactivate the p53 tumor suppressor gene, and disrupt other cancer-related genes either within or flanking the chromosomal breakpoints. This combinational effect causes the progression of mantle cell lymphoma.     

Genomic complexity and chromosomal rearrangements in wine-laboratory yeast hybrids

In this report we describe the genomic complexity of a number of Saccharomyces yeast strains isolated from sherry wine (flor yeasts), and the genomic stability of a yeast hybrid derived from one of these and a laboratory strain. Flor yeast strains largely differed in their DNA content, but showed very few variations their molecular karyotype. These strains contained a large number of Ty2 sequences, but lacking the Ty1 elements commonly found in laboratory strains. The genetic analysis of a flor-laboratory hybrid indicated that flor yeasts were aneuploid. Hybridization patterns obtained with Ty1 and Ty2 probes in the meiotic progeny of this hybrid suggested that recombination may occur not only among homologous chromosomes of similar length, but also among polymorphic partners with different sizes. New chromosomal variants were frequently observed in the meiotic products, suggesting that polymorphism in chromosome length may itself be a major source of karyotypic variation. The genetic analysis of such variants indicated that recombinational events leading to new chromosomal forms may occur both mitotically and meiotically. Received: 2 April / 26 May 1996     

Molecular cytogenetic analysis of complex chromosomal rearrangements in patients with mental retardation and congenital malformations: delineation of 7q21.11 breakpoints

Constitutional de novo complex chromosomal rearrangements (CCRs) are a rare finding in patients with mild to severe mental retardation. CCRs pose a challenge to the clinical cytogeneticist: generally CCRs are assumed to be the cause of the observed phenotypic abnormalities, but the complex nature of these chromosomal changes often hamper the accurate delineation of the chromosomal breakpoints and the identification of possible imbalances. In a first step towards a more detailed molecular cytogenetic characterization of CCRs, we studied four de novo CCRs using multicolor fluorescent in situ hybridization (M-FISH), comparative genomic hybridization (CGH), and FISH with region specific probes. These methods allowed a more refined characterization of the breakpoints in three of the four CCRs. The occurrence of 7q breakpoints in three out of these four CCRs and in 30% of reported CCRs suggested preferential involvement of this chromosomal region in the formation of CCRs. Further analysis of these 7q breakpoints revealed a 2 Mb deletion at 7q21.11 in one patient and involvement of the same region in a cryptic insertion in a second patient. This particular region contains at least 5 candidate genes for mental retardation. The other patient had a breakpoint more proximal to this region. The present data together with these from the literature provide evidence that a region within 7q21.11 may be prone to breakage and formation of CCRs.     

Complex chromosomal rearrangements: some breakpoints may have cellular adaptive significance

Cytogenetic study of a 3-year-old girl with developmental delay and some minor abnormalities revealed a complex chromosome rearrangement (CCR) involving seven chromosomes with eight breakpoints, leading to monosomy of segment 5q15-q22. According to breakpoint distribution, CCRs may be classified as those with primary intrachromosomal abnormalities (including inversions, insertions, duplications, etc.) and those without them. Only the latter group of CCRs was used in this analysis. Comparison of theoretical and observed breakpoint distributions in 33 cases demonstrated that recurrent involvement of some chromosome(s) ("re-entry") occurs more frequently than expected. One possible explanation for this observation suggests that the initial event leads to an unstable provisional rearrangement, and subsequent breaks are necessary to stabilize the karyotype.