Preimplantation genetic diagnosis by fluorescence in situ hybridization of reciprocal and Robertsonian translocations

ObjectiveThe presence of reciprocal and Robertsonian chromosomal rearrangement is often related to recurrent miscarriage. Using preimplantation genetic diagnosis, the abortion rate can be decreased. Cases treated at our center were reviewed.Materials and methodsA retrospective analysis for either Robertsonian or reciprocal translocations was performed on all completed cycles of preimplantation genetic diagnosis at our center since the first reported case in 2004 until the end of 2010. Day 3 embryo biopsies were carried out, and the biopsied cell was checked by fluorescent in situ hybridization using relevant informative probes. Embryos with a normal or balanced translocation karyotype were transferred on Day 4.ResultsThirty-eight preimplantation genetic diagnosis cycles involving 17 couples were completed. A total of 450 (82.6%) of the total oocytes were MII oocytes, and 158 (60.0%) of the two-pronuclei embryos were biopsied. In 41.4% of the fluorescent in situ hybridization analyses, the results were either normal or balanced. Embryos were transferred back after 21 cycles. Three babies were born from Robertsonian translocation carriers and another two from reciprocal translocation carriers. The miscarriage rate was 0%. Among the reciprocal translocation group, the live delivery rate was 8.3% per ovum pick-up cycle and 18.2% per embryo transfer cycle. Among the Robertsonian translocation group, the live delivery rate was 14.3% per ovum pick-up cycle and 20.0% per embryo transfer cycle.ConclusionThere is a trend whereby the outcome for Robertsonian translocation group carriers is better than that for reciprocal translocation group carriers. Aneuploidy screening may possibly be added in order to improve the outcome, especially for individuals with an advanced maternal age. The emergence of an array-based technology should help improve this type of analysis.     

Poor prognosis of recurrent aborters with either maternal or paternal reciprocal translocations

OBJECTIVE: To determine whether the miscarriage rate in recurrent miscarriage patients with an abnormal karyotype, especially reciprocal translocations, in either partner is worse than without an abnormal karyotype. DESIGN: Retrospectively analyzed prospectively obtained database. SETTING: Nagoya City University Hospital. PATIENT(S): One thousand and two hundred eighty-four couples with a history of 2 or more (2 to 12) consecutive first-trimester miscarriages. INTERVENTION(S): Patients with antiphospholipid antibodies were treated with low-dose aspirin and combined therapy. MAIN OUTCOME MEASURE(S): Subsequent miscarriages were compared for cases with and without an abnormal karyotype in either partner. A karyotype analysis was also conducted for each aborted conceptus and offspring of 95 pregnancies of 47 patients with reciprocal translocations. RESULT(S): Of the total of 1,284 couples, 58 (4.5%) had translocations, 11 being Robertsonian translocations. Eleven of the 18 cases (61.1%) where the husband had a reciprocal translocation suffered further miscarriage; this also was the case for 21 of the 29 cases (72.4%) where the wives had a reciprocal translocation. Those with reciprocal translocations in either partner miscarried significantly more frequently than those without an abnormal karyotype. Only one infant with an unbalanced translocation was found in 34 cases of successful pregnancy following habitual abortion. CONCLUSION(S): The pregnancy prognosis with either maternal or paternal reciprocal translocations is poorer than without them. The presence of a reciprocal translocation is thus a risk factor in couples who have recurrent miscarriages.     

Three hundred and thirty cycles of preimplantation genetic diagnosis for serious genetic disease: clinical considerations affecting outcome

OBJECTIVE: To report on our experience with preimplantation genetic diagnosis (PGD) cycles performed for serious genetic disease in relation to the clinical factors affecting outcome. DESIGN: Retrospective review of data from a single centre. SETTING: Tertiary referral PGD centre in a London teaching hospital. METHODS: The PGD cycles included 172 cycles for chromosome rearrangements, 96 cycles for single-gene disorders and 62 cycles for X-linked disorders. In vitro fertilisation was the preferred method in chromosome rearrangement and X-linked cases, while intra cytoplasmic sperm injection was used in all single-gene disorders. Appropriate in situ hybridisation fluorescence probes were used in chromosome rearrangement and X-linked cases and polymerase chain reaction was used in single-gene disorders. All pregnancies were followed till delivery. MAIN OUTCOME MEASURE: Live birth rate per PGD cycle started. RESULTS: Eighty-six percent of cycles started (283) reached oocyte retrieval and 3743 eggs were collected, of which 2086 fertilised normally (55.7%). Two hundred and fifty cycles (76%) had embryos sutiable for biopsy on day 3 of in vitro culture, 1714 embryos were biopsied, and in 205 cycles (62%), there was at least one unaffected embryo available for transfer, resulting in 90 pregnancies, 68 clinical pregnancies and 58 live birth. The live birth rate was 18% per cycle started, 21% per egg retrieval and 28% per embryo transfer which significantly affected the live birth outcome. Woman age, number of eggs collected and achieving cryopreservation of surplus embryos had no statistically significant effect on treatment outcome. CONCLUSIONS: The live birth outcome of PGD cycles for serious genetic disorder is modest and is affected by the number of embryos genetically suitable for transfer.     

Higher degree of chromosome mosaicism in preimplantation embryos from carriers of robertsonian translocation t(13;14) in comparison with embryos from karyotypically normal IVF patients

Purpose : To compare the frequency and the degree of mosaicism in human embryos from Robertsonian translocation (RT) t(13;14) carriers, with embryos from karyotypically normal IVF patients. Methods : FISH analysis of embryos from PGD cycles for RT t(13;14), with probes for chromosomes 13, 14, and 18 (Group I) and of embryos from karyotypically normal IVF patients with probes for chromosomes 13, 18, 21, X, and Y (Group II). Results : The incidence of abnormal mosaic embryos was significantly higher in group I (38/51) as compared with group II (6/45) (²: P < 0.01). Furthermore, in group I the percentage of diploid cells per embryo was lower for chromosome 13 and 14 in comparison with 18, while in group II no differences were observed between the five chromosomes analyzed. Conclusions : RT induces a high frequency of mosaicism specifically for the chromosomes implicated in the translocation; the analysis by FISH of two blastomeres is strongly recommended for these patients.     

Public perspectives on the use of preimplantation genetic diagnosis

Purpose

To study the perspectives of the United States population towards the use of preimplantation genetic diagnosis (PGD) in various clinical scenarios.

Methods

Online cross-sectional population based questionnaire of a nationally representative sample according to age, gender, race/ethnicity, income, education and religion.

Results

A total of 1006 completed the questionnaire with an overall response rate of 94 %. A majority supported PGD for diseases fatal early in life or those causing lifelong disability (72.9 and 66.7 %, respectively); only 48.0 % supported PGD for diseases that manifest late in life. Respondents were more supportive of PGD for genetic diseases if they were aware of PGD prior to the survey (OR = 1.64; CI = 1.13–2.39). However, a small proportion were in favor of genetically-based trait selection: 21.1 % supported PGD for sex selection, 14.6 % for physical traits and 18.9 % for personality traits. Compared to women, men were nearly two- to three-fold more supportive of PGD for sex selection (OR = 1.65; CI = 1.20–2.78), physical traits (OR = 2.38; CI = 1.60–3.48) and personality traits (OR = 2.31; CI = 1.64–3.26). Compared to Caucasians, Asians (OR = 3.87; CI = 1.71–8.78) and African Americans (OR = 1.61; CI = 1.04–2.74) were more supportive of PGD for sex selection.

Conclusions

In a nationally representative sample, a majority supported PGD to identify early onset diseases. We noted significant variation in opinions by sex, race, and education. There was more support among those with prior knowledge of PGD suggesting that education about PGD may foster favorable opinions. This study identifies public knowledge and attitudes that may be used to shape future research hypotheses and clinical policies.     

植入前遗传学诊断及筛查技术相关伦理问题

文章阐述了植入前遗传学诊断及筛查技术中遭遇的主要伦理问题,包括：（1）准父母的需求与适应证的确定之间的矛盾。（2）检测结果的解读方式对准父母的理解决定的影响。（3）知情同意、配子胚胎的权利归属、各方责任约定和各类胚胎最终去向的协商。（4）新技术可能带来的新的伦理问题。     

二代测序技术在植入前遗传学诊断中的应用

二代测序技术在植入前遗传学诊断、筛查中的应用正在迅速发展,其不仅能进行胚胎染色体的全面筛查和诊断,还能检测单基因病。文章就二代测序技术在染色体病、单基因病的植入前     

染色体易位-胚胎植入前诊断的研究进展

染色体易位携带者有较高的发生不良妊娠结局的风险,主要源自高概率的非均衡配子。对于染色体易位的携带者,进行胚胎植入前遗传学诊断(preimplantation genetic diagnosis,PGD)可以改善妊娠结局。目前,临床应用的非平衡易位诊断的方法主要有比较基因组杂交微阵列(comparative genomic hybridization array,array CGH)、单核苷酸多态性微阵列(single nucleotide polymorphism array,SNP array)和二代测序(next generation sequencing,NGS);荧光原位杂交(fluorescence in situ hybridization,FISH),能够区分平衡易位和正常胚胎,可能实现的技术有NGS。此外,平衡易位的诊断是否有必要开展尚存在争议。     

Analysis of sex chromosomes in preimplantation genetic diagnosis for X-chromosome-linked disorders

Preimplantation genetic diagnosis (PGD) is diagnostic tool to avoid inheritance of genetic disease by transferring unaffected embryos. Recently, PCR and FISH have been mainly applied to the diagnosis of single gene disorders and chromosomal abnormalities, respectively. Since with PGD, only a few cells are available for genetic tests, both gene and chromosomes analysis have to be obtained from the same, limited material. Cell recycling makes it possible to obtain the information on genes as well as chromosomes from the same cells. Therefore cell recycling is an acceptable strategy where in PGD targets large proportions of embryos severe chromosomal abnormalities. The responsible genes of the X-linked disorder and numerical abnormalities of sex chromosomes should be analyzed simultaneously. Gender information is definitely useful because only male affected embryos should be avoided for transfer.