荧光原位杂交技术分析足月小样儿染色体畸变一例

患儿男,足月小样儿,胎龄40周,出生体重2200 g,头围28cm,身长45cm.患儿呈现小颅、扁平脸、宽额,小眼且睑裂狭小,耳小低位,小鼻.鼻梁较低且鼻根宽大.全身体格检查未发现明显异常,超声检查未见内脏异常,初步怀疑患儿可能存在染色体异常.染色体核型分析显示患儿父亲为46,XY,t(10;15)(q25;q26),为表型正常的相互易位携带者;患儿母亲为46,XX,核型正常;患儿核型为46,XY,-15.+der(15)t(10;15)(q25;q26)pat.为了寻找染色体易位断点,选择位于10q24的RP11-170O19探针和位于10q26.2的RP11-31A20探针进行荧光原位杂交(nuorescence in situ hybridization,FISH)分析.结果显示RP11-170O19探针与两条10号染色体的长臂均有杂交,RP11-31A20探针除与两条10号染色体的长臂均有杂交外,还与衍生的15号染色体长臂有杂交.     

冻融胚胎行植入前遗传学诊断后妊娠并分娩一例

患者25岁,因"原发不孕,男方重度少弱精,男方染色体异常"就诊.由于男方染色体核型为45,XY,der(13;14)(q10;q10),拟行胚胎植入前遗传学诊断(preimplantation genetic diagnosis,PGD);2007年7月进行体外受精(IVF)周期,IVF后第3天,冻存2枚5细胞以上的胚胎;2007年11月将这2枚胚胎冻融行PGD.     

染色体易位的植入前遗传学诊断

目的 观察染色体平衡易位和罗伯逊(罗氏)易位基因携带者夫妇进行植入前遗传学诊断(PGD)后的胚胎染色体遗传特征和胚胎着床、妊娠情况,探讨PGD在染色体易位基因携带者夫妇实现正常生育中的意义.方法 用荧光原位杂交(FISH)技术对36对夫妇的胚胎进行PGD,其中14例为染色体平衡易位(平衡易位组),22例为染色体罗氏易位(罗氏易位组),并对诊断结果和胚胎着床、妊娠情况进行分析.结果 36例患者共活检胚胎253个,成功诊断胚胎225个,成功率为88.9%(225/253),获得可供移植的正常或平衡的胚胎共58个.平衡易位组和罗氏易位组PGD后胚胎着床率分别为36%(5/14)和14%(6/44),临床妊娠率分别为4/9和26%(5/19).结论 PGD可有效诊断胚胎染色体平衡易位和罗氏易位,避免反复流产和不必要的非意愿性终止妊娠,并获得理想的胚胎着床率和临床妊娠率.     

应用荧光原位杂交技术诊断复杂的染色体重排1例

复杂的染色体重排(CCR)足一种罕见的细胞遗传学异常,涉及到3个或更多的染色体重排,包括染色体的缺失,插入或倒位。目前,应用常规细胞遗传学及显带技术还很难对其进行准确地诊断。 患者G5P1,曾分别于12、14、20孕周发生自然流产,亦分娩过1健康男婴。流产组织(20孕周)的细胞遗传学分析显示出异常胎儿核型:46,XX,-5,-7,+der(5)t(5;7)(p15;q31),+der(7)t(7;11)(q31;q13)。此次妊娠第16周始接受产前检查,被确诊为涉及到5、7、11号染色体的CCR携带者,而其     

短串联重复序列在染色体罗氏易位植入前遗传学诊断的应用

目的:采用多重置换扩增(MDA)结合短串联重复序列(STR)建立一种基于PCR技术诊断染色体罗氏易位的植入前遗传学诊断(PGD)方法。方法:选择位于易位染色体上的STR位点,对家系采用荧光PCR进行分析,选择有多态性的位点,再采用MDA对单细胞进行全基因组扩增,根据家系分析的结果,对具有多态性的STR位点进行分析诊断。结果:对3个家系进行了4个取卵周期(3个PGD周期),每个家系分别采用7~15个具有多态性的STR位点进行分析,共对24个胚胎进行诊断。PGD的诊断效率为95.8%(23/24),平衡胚胎占52.2%(12/23),异常胚胎占47.8%(11/23),共移植了6个胚胎,获得2例临床妊娠,临床妊娠率为66.7%(2/3),出生了2个健康婴儿,染色体核型均正常。结论:采用依赖于STR的PCR分析法可以用于染色体罗氏易位的PGD。     

羊水细胞培养用于染色体病产前诊断64例分析

目的探讨用羊水细胞培养对孕中期孕妇进行产前诊断的可行性及必要性,防止染色体病患儿出生。方法2003年3月至2004年12月北京大学深圳医院采用羊水细胞培养G显带技术,对64例具有产前诊断指征的孕妇进行检查。结果发现1例世界罕见染色体异常核型46,XY,der(11)t(8;11)(q24;q25),58例正常核型,5例核型为多态,诊断结果与随访情况一致。结论羊水细胞培养进行产前诊断是十分安全而可靠的。     

t(11;22)(q23;q11)复发性染色体平衡易位——4例病案报道及文献复习

目的:初步探讨非罗伯逊型复发性t(11;22)(q23;q11)染色体平衡易位的发生机制。方法:外周血染色体核型分析检测有不孕不育或不良生育史的4例患者的染色体核型。结果:4例t(11;22)(q23;q11)易位患者,染色体断裂位点一致,患者间无亲缘关系,均有不良生育史,其中2例女性表现为反复流产,2例男性患者表现为精子数目减少和活力下降的。结论:t(11;22)(q23;q11)是一种较为少见的非罗伯逊易位型复发性平衡易位,对t(11;22)(q23;q11)深入研究有助于进一步完善染色体畸变的理论基础。     

胚胎植入前遗传学诊断10个周期的临床分析

目的:初步探讨使用荧光原位杂交(FISH)方法对染色体异常患者进行胚胎植入前遗传学诊断(PGD)的临床意义。方法:7对不孕夫妇采用长方案控制性超排和卵胞浆内单精子注射,受精后d3胚胎活检、卵裂球固定和FISH,d4或d5择合适胚胎移植。结果:7对夫妇共进行10个PGD周期。获卵251个,可供活检胚胎133个,活检卵裂球207个,胚胎活检成功率为96.2%(128/133)。128个成功活检胚胎的197个卵裂球,其单细胞固定率为93.9%(185/197),FISH信号率为90.8%(168/185)。10个周期共移植22个胚胎,3例获得妊娠,并均足月分娩健康婴儿,其中1例孕妇平衡易位携带者于孕中期时,羊水核型分析为平衡易位携带者。结论:应用FISH方法进行PGD,是遗传病高危夫妇预防流产和染色体异常患儿出生的有效手段。     

染色体平衡易位伴不良孕史3例

目的报道3例染色体平衡易位伴不良孕史的病例。方法应用G显带技术对3例伴有不良孕史的女性患者进行染色体核型分析,检测到核型异常后用荧光原位杂交技术(FISH)进行验证。结果 3例患者均为平衡易位,核型分别为t(3;5)(p13;q13.3)、inv(4)(p16q13)和ins(4;7)(p15.2;q32q34),后用FISH验证结果与核型分析相符,经查询国内外权威数据库均未见3例异常核型相同报道。结论平衡易位是不明原因反复流产的重要因素之一,携带者再次妊娠应积极配合医生进行产前诊断。     

121例遗传咨询门诊病例的细胞遗传学分析

就1982年121例遗传咨询门诊所查7例染色体异常进行报道与分析。常规进行淋巴细胞培养G显带,部分病例选加C带。7例的异常核型是:46,XX,-21,t(21q21q);46,X,i(Xq);45,X/46,XX;45,X/46,XY;45,XX,t(13q14q)mat;45,XX,t(13q14q);46,XY,nv(q)。     

Embryo development characteristics in Robertsonian and reciprocal translocations: a comparison of results with non-translocation cases

The effect of translocations on embryo development was evaluated and results were compared in terms of embryo development with those of embryos obtained from standard intracytoplasmic sperm injection (ICSI) cycles. In 23 translocation carriers with 34 cycles, fertilization, pronuclear morphology scoring (PMS), developmental arrest, cleavage and blastocyst formation were evaluated and compared with embryos obtained from non-translocation cases undergoing ICSI (n = 98 cycles). In 28 cycles, preimplantation genetic diagnosis (PGD) was performed on prezygotes (first and second polar body biopsy for female carriers; n = 3) or on embryos having seven or more blastomeres (blastomere biopsy; n = 25). In six cycles for four couples, probes for translocated chromosomes were not available, so PGD could not be performed. Overall, in translocation cases, a lower fertilization rate, a higher rate of retarded embryo development, and a lower rate of blastocyst formation were observed compared with embryos of non-translocation cases. Fluorescence in-situ hybridization (FISH) analysis showed a 70.9% abnormality rate for reciprocal translocations and 55.0% for Robertsonian translocations respectively. In cases with Robertsonian and reciprocal translocation carriers, the probability of poor embryo development, which may be a result of high segregation abnormalities, may negatively affect the outcome of assisted reproductive techniques. This poor prognosis should also be considered when genetic counselling for translocation is given.     

荧光原位杂交技术不同方案用于染色体易位携带者胚胎植入前遗传学诊断的效率比较

目的 探讨荧光原位杂交(FISH)技术不同方案用于染色体易位携带者胚胎植入前遗传学诊断(PGD)的效率.方法 根据FISH检测方案的不同进行分组:采用全染色体涂抹探针对染色体易位携带者8个周期的109个卵母细胞第一极体进行诊断(A组),采用联合端粒和着丝粒探针对染色体易位携带者29个周期的357个卵裂球进行诊断(B组),比较两组的活检成功率、固定时细胞丢失率、无核细胞数等.结果 A组的109个卵母细胞中72个受精,受精率为66.1%(72/109),B组的357个卵裂球中304个受精,受精率为85.2%(304/357),A组的受精率显著低于B组,差异有统计学意义(P<0.05).固定时细胞丢失率A组为9.6%(12/104),B组为1.6%(4/252),两组比较,差异也有统计学意义(P<0.05).杂交后核的无信号率A组为11.2%(10/89),B组为3.0%(7/233),两组比较,差异有统计学意义(P<0.05).A组的诊断率为72.5%(79/109),显著低于B组的89.8%(230/256),差异有统计学意义(P<0.05).A组的临床妊娠率和胚胎植入率分别为3/7和22.2%(4/18),均高于B组的30.4%(7/23)和15.7%(8/51),但差异均无统计学意义(P>0.05).结论 FISH两种方案均可有效地进行染色体平衡易位的PGD,卵裂球PGD的诊断效率更高.     

Molecular cytogenetic characterization of a de novo small supernumerary marker chromosome derived from chromosome 15 in a pregnancy with incidental detection of a maternal Robertsonian translocation of 45,XX,der(13;14) (q10;q10)

ObjectiveWe present molecular cytogenetic characterization of a small supernumerary marker chromosome (sSMC) derived from chromosome 15 in a pregnancy with incidental detection of a maternal Robertsonian translocation of 45,XX,der(13; 14) (q10; q10).Case reportA 37-year-old, primigravid woman underwent amniocentesis at 16 weeks of gestation because of advanced maternal age. Amniocentesis revealed a karyotype of 47,XY,+mar. Simultaneous array comparative genomic hybridization (aCGH) analysis on the DNA extracted from uncultured amniocytes showed the result of no genomic imbalance or arr (1–22) × 2, (X,Y) × 1. Cytogenetic analysis of the parents showed a karyotype of 45,XX,der(13; 14) (q10; q10) in the mother and a karyotype of 46,XY in the father. Prenatal ultrasound was unremarkable. At 38 weeks of gestation, a 2790-g phenotypically normal male baby was delivered. The cord blood had a karyotype of 47,XY,+mar. Metaphase fluorescence in situ hybridization (FISH) analysis showed the result of +mar.ish dic(15) (D15Z1++, SNRPN-, PML-) (18/20). The extra chromosome was derived from chromosome 15.ConclusionMetaphase FISH analysis is useful for the identification of the origin of an sSMC in the presence of no genomic imbalance at aCGH analysis. Prenatal diagnosis of a de novo sSMC may be associated with a Robertsonian translocation in the parents, and parental cytogenetic analysis is necessary under such a circumstance.     

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.     

Mosaicism for Robertsonian jumping translocation at amniocentesis: 45,XY,der(15;22)(q10;q10)mat/46,XY,i(15)(q10)/46,XY,genetic counseling,prenatal diagnosis and postnatal follow-up in a pregnancy with a favorable fetal outcome

ObjectiveWe present genetic counseling, prenatal diagnosis and postnatal follow-up of 45,XY,der(15;22)(q10;q10)mat/46,XY,i(15)(q10)/46,XY at amniocentesis in a pregnancy with a favorable fetal outcome.Case reportA 27-year-old, primigravid woman underwent amniocentesis at 19 weeks of gestation because increased nuchal translucency thickness, and the result was 45,XY,der(15;22)(q10;q10)[29]/46,XY,i(15)(q10)[3]/46,XY[5]. Simultaneous array comparative genomic hybridization (aCGH) analysis on the DNA extracted from uncultured amniocytes revealed arr (1–22) × 2, (X,Y) × 1. The maternal karyotype was 45,XX,der(15;22)(q10;q10), and the paternal karyotype was 46,XY. She was referred for genetic counseling, and repeat amniocentesis performed at 23 weeks of gestation revealed 45,XY,der(15;22)(q10;q10)mat[23]/45,XY,-22[2]. aCGH analysis on uncultured amniocytes detected no genomic imbalance, and polymorphic DNA marker analysis excluded uniparental disomy (UPD) 15. Fluorescence in situ hybridization (FISH) analysis using the chromosome 15q specific probe and the chromosome 22q specific probe detected three 15q signals in 4/104 cells (3.8%). The woman was advised to continue the pregnancy, and, a 3186-g phenotypically normal male baby was delivered at 38 weeks of gestation. The umbilical cord had a karyotype of 45,XY,der(15;22)(q10;q10) (40/40 cells). When follow-up at age seven months, the neonate was normal in development, the peripheral blood had a karyotype of 45,XY,der(15;22)(q10;q10) (40/40 cells), and the buccal mucosal cells had normal signals in all 100 cells.ConclusionsMosaicism for Robertsonian jumping translocations at amniocentesis can be a transient condition and can be associated with a familial Robertsonian translocation and a favorable fetal outcome. Prenatal diagnosis of a Robertsonian jumping translocation involving chromosome 15 should include UPD 15 testing to exclude UPD 15.     

A unique case of der(11)t(11;22),-22 arising from 3:1 segregation of a maternal t(11;22) in a family with co-segregation of the translocation and breast cancer

OBJECTIVE: To report the first tertiary monosomy in a pregnancy loss to a female t(11;22) carrier. METHODS: The patient was a 34-year-old G10P1 female known to have a balanced translocation t(11;22)(q23;q11.2). She had one female livebirth (a translocation carrier) and eight miscarriages. Five female relatives known to be translocation carriers had a history of breast cancer, three of them premenopausally. The patient herself had a malignant melanoma. RESULTS: During the 10th pregnancy, ultrasound showed a viable embryo at 6 weeks of gestation, but loss of embryonic heartbeat by 7.5 weeks. Culture of the products of conception at 8 weeks of gestation showed the karyotype: 46,XY,+2,der(11)t(11;22)(q23;q11.2)mat,-22[4]/45,XY,der(11)t(11;22)(q23;q11.2)mat,-22[4], resulting from fertilization of the maternal 3:1 segregation product containing only the der(11) by a normal gamete. Subsequently, she became pregnant with a normal 46,XX fetus. FISH analysis indicated that the breakpoints on 11q and 22q in the patient were in the previously described region common to typical recurrent t(11;22). In addition, a nested-PCR-based approach showed that they were located within the same palindromic AT-rich sequence previously described. CONCLUSION: This case demonstrates that the tertiary monosomy resulting from the 3:1 segregation is compatible with embryonic survival into the first trimester. It is also another example of apparent association of the constitutional translocation t(11;22) and breast cancer.     

Preimplantation genetic diagnosis (PGD): the Gothenburg experience

BACKGROUND: A program for preimplantation genetic diagnosis of pre-embryos from patients with hereditary disorders was set up in our unit at Sahlgrenska University Hospital in 1994. The majority of the patients were carriers of X-chromosome linked disorders; a few patients were translocation carriers. In this paper we describe our experiences of our first 36 cycles, 30 gender determinations and six analyses of embryos with possible translocations. METHODS: Conventional hormone replacement treatment with intracytoplasmic sperm injection to fertilize the eggs followed by blastomere biopsy and fluorescent in situ hybridization at the eight cell stage was used for sexing as well as detection of translocations. RESULTS: Out of the 30 cycles in 13 patients for gender determination, blastomere biopsies could be carried out in 25 cycles. Transfer of normal female embryos (XX) was performed in 18 cycles, resulting in five pregnancies (pregnancy rate 27.8%) and an implantation rate of 20% per transfer. Three girls have been born. Hence the take home baby rate was 16.7% per transfer and 10% per started cycle. Six cycles (three patients) for detection of translocations in embryos were performed. Diagnosis was possible in four cycles. Transfer of normal embryos was carried out in one cycle. No pregnancy was achieved. CONCLUSION: Successful PGD in its clinical application demands close collaboration between a large group of specialists. Even so, the success rate is considerably lower than after conventional IVF or ICSI procedures. Taking into account the stress caused to the parents facing late interruption of pregnancy following conventional prenatal diagnosis we are convinced that this technique is well worthwhile continuing and refining.     

Spontaneous Abortions Are Reduced After Preconception Diagnosis of Translocations

Purpose: Preimplantation genetic diagnosis of translocations has seldom been attempted. Recently, a genetic test based on analyzing polar bodies at the methaphase stage, following fluorescent in situ hybridization with commercially available whole-chromosome painting DNA probes has been presented. Here we report the use of this method in seven couples in whom the female was a carrier of one of these balanced translocations: 45,XX,der (13q;14q)(q10;q10) (two cases), 46,XX,t(4;14)(p15.3;q24), 45,XX,der(14q;21q) (q10;q10), 46,XX,t(7;20)(q22;q11.2), 46,XX,t(9,11)(p24;q12), 46,XX,t(14;18)(q22;q11), and 46,XX,t(3;8)(q11;;q11). Methods: The original method was improved in two ways. First, centromeric probes for one or both chromosomes involved in the translocation were added to avoid misdiagnosis caused by possible confusion of first polar body monovalent chromosomes (with two chromatids each) with single chromatids. Second, for cases with terminal translocations where commercially available probes do not cover telomere sequences, a telomere probe labeling the translocated fragment was added. Results: A total of 26 abnormal, 18 balanced, and 22 normal eggs was detected. Nine normal and seven balanced embryos were transferred, resulting in eight (50%) implanting, of which one spontaneously aborted. To date, the remainder have produced karyotypically normal or balanced babies and ongoing pregnancies. The rate of spontaneous abortions after preimplantation genetic diagnosis (12.5%) was significantly reduced (P < 0.001) compared to natural cycles in the same patients (95%). Conclusions: With the above improvements, the test can characterize any translocation of maternal origin and produce a high pregnancy rate and an apparently low frequency of spontaneous abortion.     

Prenatal detection of deletion 6q13q15 in a complex karyotype

OBJECTIVES: Prenatal diagnosis of a pregnancy with elevated maternal serum alpha-fetoprotein identified a karyotype with a complex chromosomal rearrangement, a Robertsonian translocation and a 6q deletion involving bands q13q15. Sonography identified mild IUGR, polyhydramnios and micrognathia. The infant presented with multiple congenital anomalies, primarily limited to the head and neck, including hypertelorism, broad nose, micrognathia, cleft palate, microglossia and low-set ears with microtia. METHODS: Amniocytes of the fetus and blood of the patient and her parents were analyzed by cytogenetics and fluorescence in situ hybridization. RESULTS: The karyotype on the fetus was 45,XX,t(3;21;20)(p12;q11.2;p11.2), del(6)(q13q15),der(13;14) (q10;q10)mat. CONCLUSION: The 13;14 Robertsonian translocation was inherited from the mother and the three-way translocation appeared to be balanced. The patient had facial dysmorphology similar to that which has been described in 6 previously reported cases with the same deletion involving 6q13q15. There was no recognizable abnormality of limbs or digits, and the autopsy did not identify defects involving the internal organs.