355例产前胎儿羊水细胞易位染色体核型分析及遗传咨询

目的分析产前羊水穿刺孕妇胎儿的易位染色体类型、遗传方式和断点,为易位染色体携带者的再发风险及妊娠结局提供遗传咨询和诊断意见。方法彩超辅助抽取羊水,常规方法进行细胞培养、收获、制片、G显带、核型分析,回顾性统计分析2014年1月～2018年9月胎儿染色体易位的发生率、常见核型、遗传方式和断点。结果 13 100例产检孕妇中共检测出355例胎儿染色体易位,发生率为2.71%(355/13 100)。临床特征为植入前产前诊断、女方为携带者和男方为携带者的检出率最多,遗传方式为父系遗传或母系遗。rob(13;14)和rob(14;21)是累及次数最多的罗氏易位核型,t(11;22)和t(4;18)是累及次数最多的相互易位核型,遗传方式以父系遗传或母系遗传。断点分析显示,相互易位染色体共累及出现482个断点,其中断点11q23、22q11和12q24累及次数最多。结论本研究的孕妇胎儿易位染色体发生率较高,rob(13;14)和t(11;22)是累及次数最多的罗氏和相互易位核型,父系遗传或母系遗传。11q23、22q11和12q24是累及次数最多的相互易位断点。分析孕妇胎儿易位染色体发生率、遗传方式、核型和断点可能易位染色体携带者的再发风险及妊娠结局提供遗传咨询和诊断意见。     

南宁地区41例平衡易位携带者的细胞遗传学分析

目的通过对2856例反复流产、不良孕产史、不孕不育等患者进行染色体结果调查,探讨染色体平衡易位携带者的临床效应。方法采用外周血淋巴细胞染色体培养技术,G显带,核型分析。结果41例染色体平衡易位携带者中,男性21例,女性20例,常一常染色体易位39例,其中包括3例罗伯逊易位;性一常染色体易位2例。主要临床表现为女性反复自然流产、不良孕产史等;男性少弱精子症及不育等。结论染色体平衡易位是导致反复流产、不良孕产史、男性少弱精子症、不育等的重要因素之一。对于这些有反复流产史、不良妊娠史、不孕不育的临床患者,进行外周血染色体核型分析十分必要。     

染色体罗伯逊易位与女性不良孕产关系探讨

目的研究罗伯逊易位与女性不良孕产史的关系。方法对2008年6月以来在我院妇产科就诊的2482例女性遗传咨询者行外周血染色体核型分析。结果 2482例女性遗传咨询者检出罗伯逊易位携带者18例,占0.73%,其中以rob(13;14)(q10;q10)为主,共计7例。这些携带者的临床表现主要为自然流产、习惯性流产、胎儿染色体异常、胎儿畸形等。女性罗伯逊易位携带者,其自然流产发生率、习惯性流产发生率、生育21三体患儿发生率、胎儿畸形发生率和胎儿染色体平衡易位发生率明显高于正常对照人群。结论罗伯逊易位与流产、习惯性流产和胎儿畸形染色体异常之间存在相关性。     

宜昌地区879例不孕不育及不良孕产史患者细胞遗传学分析

目的探讨宜昌地区不孕不育及不良孕产史患者外周血染色体异常核型出现的类型、发生率及与不孕不育及不良孕产的关系。方法对本地区879例不孕不育及不良孕产史患者,抽取外周血,培养淋巴细胞,G显带,进行染色体核型分析。结果在879例不孕不育及不良孕产史患者中有70例染色体核型异常,异常率为7.96%(70/879)。其中,相互易位3例,占异常核型的4.29%(3/70),罗伯逊易位3例,占异常核型的4.29%(3/70);染色体多态最多,共54例,占异常核型的77.14%(54/70),此外,性染色体异常共10例,占异常核型的14.29%(10/70)。结论宜昌地区不孕不育及不良孕产史患者中染色体核型异常检出率较高,主要为染色体相互易位、罗伯逊易位、染色体多态及性染色体异常。其中,染色体多态发生率最高,性染色体异常次之。     

7号染色体臂间倒位伴自然流产一例

患者　女,35岁。结婚12年,自然流产两次,均发生在妊娠2个月左右。患者表型正常,身体健康,否认家族有流产、死胎或生育畸形儿史。妇科检查无异常,孕期无服药、患病及接触有害物质史。夫妇非近亲结婚,丈夫身体健康。取患者外周血进行淋巴细胞培养,常规制片,G显带分析,核型为46,XX,inv(7)(pter→p11∷q36→p11∷q36→qter)。丈夫核型正常。讨论　夫妇染色体结构畸变是导致自然流产的原因之一,以染色体相互易位最为多见,其次是臂间倒位。习惯性流产夫妇以9号染色体臂间倒位为多,发生率明显高于一般人群,由于9号臂间倒位发生区域是异染色质区域…     

55例染色体相互易位携带者生育结局追踪及临床分析

目的探讨染色体相互易位对携带者生育的影响,为帮助类似患者选择合适的生育方式提供参考。方法对2012年1月至2013年12月因不孕不育和复发性流产就诊我科并进行外周血染色体核型分析发现的染色体相互易位携带者进行相应检查和治疗,并追踪生育结局至2015年12月,进而分析染色体相互易位对生育的影响。结果成人外周血检测共发现染色体相互易位携带者55例,核型涵盖了所有染色体。除个人原因暂避孕7例、AID4例、领养1例、失诊4例外,39例有生育意愿患者自然受孕22例,促排卵治疗3例,IVF/ICSI助孕9例,PGD助孕5例。35人妊娠38次,胚亡流产7次,单胎足月分娩25例,双胎足月分娩2例,妊娠中期2例,异位妊娠1例,胎儿畸形伴早产夭亡1例,足月分娩患者27人中进行羊水穿刺产前诊断15例16个胎儿,核型完全正常12个(46,XX/XY),同易位携带者亲本核型一致4个,共分娩29个新生儿,除一个伴隐睾外,目前表型均正常。结论对染色体相互易位携带者,除了PGD,可根据患者的具体情况,选择不同的妊娠及助孕方式,仍然可以达到理想的妊娠结局。     

67例染色体罗伯逊易位携带者的细胞遗传学分析

目的通过对7816例因反复流产、不孕不育、生长发育迟缓等患者进行外周血染色体检查结果统计分析,进一步探讨染色体罗伯逊易位的临床意义及指导临床治疗。方法采用外周血淋巴细胞染色体培养技术,通过G显带,核型分析。结果外周血染色体检查共计检测出67例染色体罗伯逊易位,其中以Rob(13q14q)和Rob(14q21q)为主,分别占65.6%(44/67)和13.4%(9/67)。结论染色体罗伯逊易位是导致反复流产、不良孕产史、不孕不育和身材矮小等的重要遗传因素。同时染色体罗伯逊易位可遗传给后代,应做好产前诊断。     

40例染色体平衡易位携带者的不同临床效应分析

目的探讨染色体平衡易位携带者的不同临床效应,为今后实施一级预防提供依据。方法采用外周血淋巴细胞染色体培养技术,G显带,显微镜下核型分析,计数30～50个核型,分析3～5个核型,必要时辅以C带。结果 40例染色体平衡易位携带者中,男18例,女22例。常-常染色体易位携带者38例,临床主要特征为反复自然流产、畸胎、畸形儿生育史及男性少弱精子、不育。表现为不良孕产史者37例,其中相互易位27例(男性11例,女性16例)、罗伯逊易位8例(男性6例,女性2例)、插入易位2例(1例核型为46,XX,ins(6;12)表现为原发闭经,另1例核型为46,XX,ins(2;6),t(3;4)表现为自然流产5次)。分别占72.97%、21.62%、5.41%。1例33岁核型为46,XX,t(8;18)的孕妇曾自然流产4次后,再次孕20周来我院要求产前诊断,产前诊断报告结果正常,孕足月顺产一正常核型男婴。性-常染色体易位携带者2例,1例Y-常染色体易位表现为无精子;1例X-常染色体易位者,表现为不孕,月经稀发。结论染色体平衡易位是导致反复流产、畸形儿生育史及不良孕产史和男性少弱精子、不育等主要原因之一,有必要对反复流产、畸形儿生育史及不良孕产史和男性少弱精子、不孕不育等夫妇双方进行染色体检查。     

染色体易位与女性不良妊娠关系探讨

目的研究染色体易位与女性不良妊娠的关系。方法对2011年1月-2016年6月在我院妇产科就诊的1482例女性遗传咨询者行外周血染色体核型分析。结果 1482例女性遗传咨询者,共检出染色体平衡易位32例,占2.16%,其中非同源罗伯逊平衡易位16例,同源罗伯逊平衡易位4例,相互平衡易位12例,临床表现主要为流产、不育、死胎和21三体患儿及畸形儿生育史等。染色体易位携带者,其自然流产发生率、因胎儿畸形或者染色体异常引产发生率、生育21唐氏综合征患儿发生率和胎儿染色体平衡易位发生率明显高于正常对照人群。结论染色体易位是导致女性流产、胎儿畸形或者胎儿染色体异常的重要原因之一。     

620对不孕不育及不良孕产史夫妇细胞遗传学分析

目的通过对临床表现为不孕不育及不良孕产史就诊的夫妇进行外周血染色体核型分析,了解染色体异常与不孕不育及不良孕产史的关系。方法对620对不孕不育及不良孕产史夫妇采集静脉血,淋巴细胞培养,G显带,核型分析,必要时增加C显带或N显带。结果 620对不孕不育及不良孕产史夫妇的1240份样本中检出102例异常核型,异常发生率8.2%。其中相互易位18例,插入易位1例,罗氏易位5例,倒位35例,性染色体异常11例,标记染色体2例。染色体多态变异患者检出30例,检出率2.4%。结论染色体异常是不孕不育及不良孕产史的重要影响因素,对不孕不育及不良孕产史夫妇进行细胞遗传学分析有助于明确病因。     

Identification of cryptic imbalance in phenotypically normal and abnormal translocation carriers

Approximately one in 500 individuals carries a reciprocal translocation. Of the 121 monosomy 1p36 subjects ascertained by our laboratory, three independent cases involved unbalanced translocations of 1p and 9q, all of which were designated t(1;9)(p36.3;q34). These derivative chromosomes were inherited from balanced translocation carrier parents. To understand better the causes and consequences of chromosome breakage and rearrangement in the human genome, we characterized each derivative chromosome at the DNA sequence level and identified the junctions between 1p36 and 9q34. The breakpoint regions were unique in all individuals. Insertions and duplications were identified in two balanced translocation carrier parents and their unbalanced offspring. Sequence analyses revealed that the translocation breakpoints disrupted genes. This study demonstrates that apparently balanced reciprocal translocations in phenotypically normal carriers may have cryptic imbalance at the breakpoints. Because disrupted genes were identified in the phenotypically normal translocation carriers, caution should be exercised when interpreting data on phenotypically abnormal carriers with apparently balanced rearrangements that disrupt putative candidate genes.     

Translocations as a mechanism for homozygous deletion of 13q14 and loss of the ATM gene in a patient with B-cell chronic lymphocytic leukemia

Chromosomal aberrations detected by fluorescence in situ hybridization (FISH) on interphase nuclei are important prognostic markers in chronic lymphocytic leukemia (CLL). Deletions in 13q14 and in 11q22.3 are two of the most frequent aberrations in this disease entity (55 and 18%, respectively) and are usually effected by interstitial deletions. Here, we report on the case of a 66-year-old woman with CLL who was analyzed by conventional metaphase cytogenetics as well as fluorescence in situ hybridization. Deletion-specific probes detected a homozygous loss of two anonymous loci in chromosomal band 13q14 in parallel with a heterozygous loss of the ATM gene located in chromosomal band 11q22.3. Karyotype analysis indicated reciprocal but unbalanced translocations involving chromosomes 3, 11, and 13. Deleted sites on 13q14 appeared to be located within the breakpoint regions of the translocations. We show that mechanisms other than interstitial deletions may lead to loss of critical chromosomal regions in CLL.     

Possible interchromosomal effect in embryos generated by gametes from translocation carriers

BACKGROUND: The incidence of abnormal pregnancies in carriers of balanced translocations depends strictly on the chromosomes involved in the translocations. The aim of this study was to verify whether conventional aneuploidy screening could be advantageously combined with preimplantation genetic diagnosis (PGD) for translocations. METHODS: Twenty-eight carriers of Robertsonian and reciprocal translocations underwent 43 PGD cycles; specific probes were used to screen the translocation in 172 embryos generated by 35 cycles; most of these embryos were also screened for chromosomes 13, 16, 18, 21, 22 (n = 166), XY (n = 107), 1 (n = 17) and 15 (n = 88). For the remaining eight cycles (carriers of reciprocal translocations) only the chromosomes involved in common aneuploidy screening were investigated on the 40 embryos generated in vitro. RESULTS: In Robertsonian translocations, the proportion of embryos with abnormalities due to the translocation was 21%, common aneuploidies contributed 31% of total abnormalities, whereas the remaining 36% of embryos had abnormalities due to both types of chromosome. For reciprocal translocations, the chromosomes involved in the translocation were responsible for 65% of total abnormalities; only 6% of the embryos were abnormal for common aneuploidies and 16% carried abnormalities due to both the chromosomes involved in the translocation and those not related to the translocation. CONCLUSIONS: An interchromosomal effect seems to play a role in the case of Robertsonian translocations, where the relevant contribution of aneuploidy exposes the couple to an additional risk of abnormal pregnancy.     

Involvement of a palindromic chromosome 22-specific low-copy repeat in a constitutional t(X; 22)(q27;q11)

Segmental duplications or low-copy repeats (LCRs) on chromosome 22q11 have been implicated in several chromosomal rearrangements. The presence of AT-rich regions in these duplications may lead to the formation of hairpin structures, which facilitate chromosomal rearrangement. Here we report the involvement of such a low-copy repeat in a t(X;22) associated with a neural tube defect. Molecular analysis of the chromosomal breakpoints revealed that the chromosome 22 breakpoint maps in the palindromic non-AT-rich NF1-like region of low-copy repeat B (LCR-B). No palindromic region was encountered near the breakpoint on chromosome X. Our findings confirm that there is no single mechanism leading to translocations with chromosome 22q11 involvement. Because LCR-B does not contain genes involved in neural tube development, we believe that the gene responsible for the observed phenotype is most likely localized on chromosome X.     

Segregation analysis in reciprocal translocation carriers

Segregation analysis of the offspring of balanced translocation carriers was performed on 327 pedigrees collated from published sources and personal communications. Correction was made for bias of ascertainment. Translocations studied involved chromosome arms 1p, 4q, 6p, 6q, 7p, 8p, 10p, 10q, 11q, 14q, 16q, and 17p. Findings included similar rates of occurrence of abnormal liveborn offspring in male and female carriers except for a reduction of risk in male carriers of translocations segregating by 3:1 mode; an elevated risk of fetal loss (spontaneous abortions and stillbirths) in female carriers of 6q, 11q, and 16q translocations compared to male carriers of these translocations; a fetal loss rate exceeding general population estimates in female carriers of 6q and 10q translocations and in male carriers of 6p, 8p, 10q, and 14q translocations including a rate of nearly 50% among female 6q translocation carriers; a higher than expected number of balanced carriers among liveborn offspring; and a low risk of abnormal liveborn children among carriers ascertained by means other than through unbalanced probands. We propose that some translocation carriers may be helped by consideration of more specific empiric risk figures than have traditionally been used.     

Multiple reciprocal translocations in salivary gland mucoepidermoid carcinomas

Mucoepidermoid carcinoma, the most common human malignant salivary gland tumor, can arise from both major and minor salivary glands, including sites within the pulmonary tracheobronchial tree. We performed comparative genomic hybridization (CGH) and spectral karyotyping (SKY) on two tumor cell lines: H3118, derived from tumor originating in the parotid gland, and H292, from tumor in the lung. In both cell lines, CGH showed a partial gain within the short arm of chromosome 7 and SKY revealed the presence of the previously reported reciprocal translocation t(11;19)(q21;p12). Additional chromosomal rearrangements were found in both cell lines, including three more reciprocal translocations in cell line H292 [t(1;16), t(6;8)x2] and three other reciprocal translocations in cell line H3118 [t(1;7), t(3;15), and t(7;15)]. A review of the literature of other reported cases of mucoepidermoid carcinomas analyzed with standard G-banding techniques, as well as distinct benign salivary gland tumors, such as pleomorphic adenomas and Warthin tumor, confirmed the presence of a karyotype dominated by reciprocal translocations. Four chromosomal bands were involved in chromosomal translocations in both cell lines: 1q32, 5p15, 7q22, and 15q22. Fluorescence in situ hybridization studies showed that the breakpoints in these four bands were often within a few megabases of each other. The involvement of similar chromosomal bands in breakpoints in these two cell lines suggests that these regions may be predisposed or selected for chromosomal rearrangements in this tumor type. The presence of multiple reciprocal translocations in both benign and malignant salivary gland tumors may also suggest a particular mechanism within mucous or serous glands mediating chromosomal rearrangements.     

Chromosomes in Ewing's sarcoma. I. An evaluation of 85 cases of remarkable consistency of t(11;22)(q24;q12)

Since our initial reports on chromosomal studies in eight Ewing's sarcomas (ES), we have carried out similar investigations on 23 additional ES specimens following short-term culture of tumor cells (16 cases), and established in vitro cell lines (three cases) and on xenografted tumors in nude mice (four cases). We demonstrated the presence of the reciprocal t(11;22)(q24;q12) in every case except one that exhibited a complex t(11;22;14)(q24;q12;q11). On the basis of results from these additional 23 cases, we confirm the consistency of the t(11;22)(q24;q12) in ES. Moreover, we reviewed 54 ES cases reported by other investigators; when added to our 31 cases, this brings the total number to 85 unrelated cases of ES available for an evaluation of the frequency of involvement of bands 11q24 and 22q12 in translocations in ES. The standard t(11;22)(q24;q12) proved to be a remarkably consistent event, present in 83% of the cases. Five percent of the cases exhibited complex translocations involving a third chromosome in addition to chromosomes #11 and #22. In 4% of the cases variant translocations involved 22q12 but with a chromosome(s) other than #11. The breakpoint on chromosome 22q12 appears to be the most consistently observed event in 92% of the cases, whereas, the breakpoint at chromosome 11q24 was observed in 88% of the cases.     

Genomic alterations in lung adenocarcinomas detected by multicolor fluorescence in situ hybridization and comparative genomic hybridization

We used two molecular cytogenetic techniques, multicolor fluorescence in situ hybridization (M-FISH) and comparative genomic hybridization (CGH), to analyze three established lung adenocarcinoma cell lines (A549, H1650, and SPC-A-1) and primary lung adenocarcinoma samples, to identify common chromosomal aberrations. M-FISH revealed numerous complex chromosomal rearrangements. Chromosomes 5, 6, 11, 12, and 17 were most frequently involved in interchromosomal translocations. CGH revealed regions on 1q, 2p, 3q, 5p, 5q, 7p, 8q, 11q, 12q, 14q, 16p, 17p, 19q, 20q, 21q, and 22q to be commonly overrepresented and regions on 2q, 3p, 4p, 5q, 7q, 8p, 9p, 13q, 14q, and 17p to be underrepresented. The most common gains were found in 16p13 (in 50% of samples), and 16p13 amplification was associated with relatively poor differentiation and late stage. M-FISH and CGH can be a powerful tool in identification of genomic alterations in lung cancer, as well as in diagnosis. The overrepresented regions may harbor potential candidate genes involved in lung adenocarcinoma pathogenesis.     

Molecular cytogenetic mapping of recurrent chromosomal breakpoints in tenosynovial giant cell tumors

Tenosynovial giant cell tumor (TGCT) is the most common benign tumor of synovium and tendon sheath. Cytogenetic data indicate that 1p11-13 is the region most frequently involved in structural rearrangements. With the aim of eventually identifying the genes associated with TGCT development, we have investigated 1p11-13 breakpoints using fluorescence in situ hybridization (FISH) analysis, with a panel of yeast artificial chromosome (YAC) probes covering 1p11-21. Twenty-six tumors were analyzed by G-banding, and 24 of these showed a breakpoint in 1p11-13. The cytogenetic findings add to previous observations that, among a variety of translocations involving 1p11-13, chromosome 2 is the most common translocation partner, with a breakpoint in 2q35-37. This aberration was found in eight cases. Other recurrent translocation partners, found in two or three cases, were 5q22-31, 11q11-12, and 8q21-22. Material from 21 tumors was available for FISH analysis, which revealed that the breakpoints clustered to one region spanned by two YAC probes, 914F6 and 885F12 located in 1p13.2, in 18 cases. Bacterial artificial chromosome probes were used to map the recurrent breakpoint on chromosome 2. In four of seven cases there was a breakpoint within the sequence covered by probe 260J21, where the RDC1 gene is located, a gene reported to fuse with HMGIC in lipomas with a 2;12 translocation.     

Jumping translocations of 11q in acute myeloid leukemia and 1q in follicular lymphoma

Jumping translocation is a rare cytogenetic aberration in leukemia and lymphoma, and its etiologic mechanisms are not clearly known. We report two cases with jumping translocations. One had follicular lymphoma and jumping translocations of 1q onto the telomeric regions of 5p, 9p, and 15q in three cell lines, co-existing with the specific translocation t(14;18)(q32;q21). The second case had acute myeloid leukemia (AML) and jumping translocations of 11q as the sole aberration, onto multiple derivative chromosomes in each of the abnormal cells. A total of 17 telomeric regions were seen as the recipients of 11q in this case, and 9q was always involved as one of the recipients in all abnormal cells. Fluorescence in situ hybridization (FISH) confirmed the identification of 11q material in the derivative chromosomes. While 1q has been the most common donor of acquired jumping translocations, this is the first report on jumping translocations of 11q. Different from all previously reported jumping translocations which involve only one recipient in each cell line and lead to a mosaic trisomy, multiple recipients in most of the abnormal cells in this case had led to a tetrasomy, or a pentasomy of 11q. The pattern of chromosome involvement as the recipients of 11q appears to show a continuing evolutionary process of jumping, stabilization, and spreading of the donor material into other chromosomes. Somatic recombinations between the interstitial telomeric or subtelomeric sequences of a derivative chromosome and the telomeric sequences of normal chromosomes are believed to be the underlying mechanism of jumping translocations and their clonal evolution.