反复自然流产夫妇染色体核型分析

目的:通过对反复自然流产夫妇的染色体核型进行分析,探讨反复自然流产与染色体核型异常的关系。方法:对1018对诊断为反复自然流产的夫妇,采集肘静脉血液,常规外周血细胞培养和染色体标本制备,行染色体核型分析。结果:1018对反复自然流产患者中,染色体异常者129例,占受检夫妇的12.67%。其中,平衡易位24例;罗伯逊易位12例;染色体多态80例;倒位11例;重复2例。结论:染色体核型异常是造成流产、死胎的重要因素之一,对反复自然流产患者进行细胞遗传学检查具有重要意义。     

染色体多态性与临床效应及生殖关系的探究

为了探讨人类染色体结构多态性与生殖异常临床效应的关系,按常规技术方法制备外周血淋巴细胞染色体,经G、C显带,对1 414例遗传咨询者进行核型分析,检出异常核型273例。其中多态性变异180例,占65.93%,非多态性异常核型93例,占34.07％。多态性变异包括D、G组短臂增长10例,次缢痕增长(包括1、9和16号染色体)35例,大Y染色体和小Y染色体 99例,Y染色体臂间倒位6例,9号染色体臂间倒位30例。结果表明,人类染色体多态性与流产、不孕不育、死胎、生育畸形儿等有相关性。     

826例遗传咨询病人的染色体分析

对826例遗传咨询病人的外周血淋巴细胞作了G带显染色体分析,检出异常核型128例,占15.5％。某中鉴定为世界首报核型5种,国内尚未见报道的3种。     

131例原发性闭经女性的细胞遗传学分析(含世界首报异常核型3例)

原发性闭经是一种原因复杂的疾病, 染色体异常则是发病的主要原因。通过对131例原发性闭经患者的外周血淋巴细胞染色体的G带核型分析, 发现其中83例为正常女性核型, 占63.36%; 各种异常核型48例,占36.64%, 其中包括3例世界首次报道的异常核型[46,X,t(X;1)(q22;p34); 46,X,t(X;5;6)(p11.2;q35;q16); 46,XX,t(4; 9)(q21;p22),t(6;10)(p25;q25),t(11;14)(q23;q32)]。另外, 将33例Turner’s综合征患者的主要异常体征及核型分布分别与Elsheikh等的报道进行比较, 发现矮身材、蹼颈、后发迹低和肘外翻的发生率与文献资料存在显著差异, 说明东西方Turner’s综合征患者临床体征的表现可能存在差异。通过对2例X-常染色体易位携带者的分析, 认为Xp11.2和Xq22区域可能与原发性闭经有关。     

中华沙鳅染色体核型

采用PHA和秋水仙素活体注射方法制备了中华沙鳅头肾组织染色体标本并分析其核型。结果表明,中华沙鳅二倍体染体色数目为96,核型公式为:2n=8m+12sm+20st+56t,臂数NF=116,无异形染色体分化。通过与其他鳅科鱼类染色体核型比较,推测中华沙鳅核型是鳅科祖先经过罗伯逊易位、染色体类型转变、染色体多倍化等途径进化而来。     

药用植物刺五加染色体核型分析

采用根尖压片技术对刺五加的细胞染色体计数,并对其进行了核型分析,结果表明：刺五加染色体数目为2n=48,染色体基数X=24。其中1对染色体上有随体,核型公式为：K（2n）=48=12m＋18sm（SAT）＋8st＋10t。染色体相对长度组成2n=4L＋22M2＋14M1＋8S,属于“3B”型。全组染色体总长30．82¨m,长臂总长22．88Dm,核型不对称系数为74．23％。     

229例流产绒毛染色体核型分析及两种长期培养方法比较

目的:探讨早期自然流产绒毛染色体核型分析在自然流产病因检测中的应用价值,并比较两种长期培养方法的差别。方法:选择孕早期自然流产的孕妇229例,在无菌条件下,从宫腔内取出绒毛,同时或单独经胰酶消化法与切碎贴壁法进行细胞培养,传代之后常规进行G显带,在显微镜下做核型分析。结果:229例流产胎儿绒毛,培养成功206例,成功率为89.96%。异常核型105例,异常率为50.97%,数目异常者101例,占异常核型的96.19%,以16三体最为多见。胰酶消化法的培养成功率及收获时间都显著优于直接贴壁法,差异具有统计学意义(P0.05)。结论:自然流产绒毛染色体核型分析对流产查因具有实用价值。胰酶消化法较切碎贴壁法对流产绒毛长期培养及染色体核型分析更具实用性。     

不同产地木耳菜的染色体核型分析

为了研究木耳菜核型特征及不同产地间的进化关系,以来自7个产地的8个木耳菜品种为材料,采用常规压片法进行核型分析,并进行核型进化趋势分析和主成分分析。结果表明:(1)所有木耳菜的染色体数目均为2n=2x=44,未见异常染色体,染色体类型均为中部着丝粒染色体(m)或近中部着丝粒染色体(sm),且m数量多于sm。(2)不同产地的木耳菜在染色体核型公式、核型类型、随体位置、染色体长度比、臂比及核型不对称系数等指标均存在明显差异;随体均为1对,但随体位置不同。(3)核型类型为1A、1B和2A型,其中1A型5种,数量最多。(4)染色体长度比范围为1.51~2.06,平均臂比值范围为1.30~1.48,仅有吉林‘利丰’和江西‘航城’存在臂比大于2的染色体。(5)核型不对称系数范围为56.25%~59.17%,核型的对称程度较高,推测木耳菜的进化程度较为原始,其中河北‘金发’是最原始,江西‘航城’最进化。研究结果为木耳菜的细胞遗传学研究提供了参考依据。     

内葵杂3号染色体核型分析

对内蒙古地区的栽培品种内葵杂3号三交种和单交种了进行了核型分析。其结果为:内葵杂3号三交种和单交种的染色体数均为2n=34,各具一对随体染色体。三交种第2对染色体具随体且为近中部着丝粒染色体,其余为中部着丝粒染色体,染色体相对长度变异范围4.105%～7.703%,核型公式为2n=2x=34=32m+2sm(2sat),核型类型属于1A型;单交种均为中部着丝粒染色体,第4对染色体具随体,染色体相对长度变异范围3.661%～8.128%,其核型公式为:2n=2x=34=34m(2sat),核型类型属于1B型。     

河南科大发现2例世界首报人类染色体异常核型

近日．河南科技大学医学院医学遗传学教研室将发现的2名女患者染色体之间的相互易位检验报告显微照片上报国内唯一的遗传学权威机构——中国医学遗传学国家重点实验室。经该实验室专家夏家辉院士、戴和平教授等共同签名认证,得出结论为：本次发现的2例异常核型,经查询,国内、国外资料目前未见报道,是2种全新的“世界首报人类染色体异常核型”。     

A specific chromosomal abnormality in rhabdomyosarcoma

A specific chromosomal abnormality, t(2;13)(q35;q14), was discovered in five cases of advanced rhabdomyosarcoma. It was identified directly in cells that had metastasized from bone marrow in one patient and in xenografts derived from the tumors of four other patients. The translocation was not restricted by histologic subtype, but was found in cases classified as alveolar, undifferentiated, or embryonal. Cytogenetic hallmarks of gene amplification (double minute chromosomes and homogeneously staining regions) were apparent in three cases. Other frequent abnormalities included rearrangements of chromosomes lp and trisomy of chromosome 8. The absence of the t(2;13) in more than 100 cases of other pediatric solid tumors investigated in our laboratory indicates its specificity for rhabdomyosarcoma. These cytogenetic findings suggest directions for further investigation of the molecular events underlying the genesis of this tumor.     

Prenatal diagnosis and characteristics of chromosome aberrations in families with genetic risk

Characteristics of the chromosomal aberrations diagnosed in 959 prenatal tests in the II trimester of pregnancy is presented. Chromosomal aberrations were diagnosed in 33 tests (3.4%). Twenty one out of these aberrations (2.2%) were of labile character. Six aberrations resulted from the parental segregation, translocation or chromosomal inversion. In 12 cases fetus inherited stable aberration from one of parents. It amounted to 1.2% of all tested cases. Chromosomal aberrations were diagnosed in 2.7% cases tested due to the risk related to the mother's age. Half of them was trisomy of chromosome 21. Chromosomal aneuploidy in the progeny of families with a child with the same abnormality was diagnosed in 1.6% of cases. Chromosomal mosaicism was diagnosed in 2.2% of cases including 0.2% of cases with true mosaicism and 1.98% of cases with pseudomosaicism. Incidence and type of the diagnosed chromosomal aberrations coincided with foreseen aberrations for each group of the genetic risk.     

应用端粒区带涂染探针检测染色体微小结构重排

为了评估染色体端粒区带涂染探针在遗传诊断的应用价值,应用显微切割获得的11q、12q和22q等3个染色体端粒区涂染探针（11q23.3→qter,12q24.1→qter,22q13.1→qter）,通过荧光原位杂交技术分析两个疑有染色体末端微小易位的习惯性流产病例。结果显示,病例1和病例2分别为t(11;12)和t(11;22)长臂末端间的微小易位,结合G显带技术确定断裂位点位于11q23.3、12q24.1、22q13.1。结果表明特异性染色体端粒区带探针可以确诊染色体末端区域的微小结构异常,可作为一种检出隐匿易位携带者并确定断裂位点的方法。     

Genetic changes in human fetuses from spontaneous abortion after in vitro fertilization detected by comparative genomic hybridization

The in vitro fertilization (IVF) technique is becoming a very important approach for infertile disease therapy, but approximately 30% of pregnancies are spontaneously aborted in the first trimester. It is believed that chromosomal abnormality is the major reason for early spontaneous abortion. Although some reports have mentioned cytogenetic changes in spontaneously aborted embryos after IVF, little is known about the comprehensive cytogenetic alterations in these aborted embryos. Here we use the comparative genomic hybridization (CGH) technique to analyze the genetic alterations in 41 spontaneously aborted human specimens after IVF. In this study, 25 of 41 cases (61%) showed chromosomal changes. Among them, autosomes and sex chromosomes were involved in 16 and 11 cases, respectively. Several nonrandom chromosomal changes were identified, including loss of one sex chromosome (six cases) and gains of 22 (four cases), Y (four cases), 21 (three cases), 4 (two cases), and 13 (two cases). Our data support the opinion that chromosome abnormality is one of the major causes of early spontaneous abortion after IVF. The association between chromosome changes in these spontaneously aborted fetuses and maternal age, infertility patterns, infertility causes, and IVF patterns (routine IVF and other methods, including intracytoplasmic sperm injection, egg donation, and embryo donation) were also studied. No significant correlation was found.     

A case with laryngeal atresia and partial trisomy 9 due to maternal 9;16 translocation.

A newborn with a partial trisomy 9 and a partial trisomy 16q is described. The child died shortly after birth because of laryngeal atresia. The chromosome anomaly was the result of a 3:1 segregation of a maternal translocation t(9;16) (q22;q24). The pertinent literature on both partial trisomy 9 and partial trisomy 16q is reviewed. All cases with partial trisomy 9 were either de novo or the result of a maternal translocation, possibly indicating the influence of imprinting on this chromosomal abnormality. The relationship between the laryngeal atresia and other features in the patient and the chromosome anomalies remains uncertain.     

Chromosomal Abnormality and Y Chromosome Microdeletion in Chinese Patients with Azoospermia or Severe Oligozoo-spermia

Chromosomal abnormality and Y chromosome microdeletion are regarded as two frequent genetic causes associated with spermatogenic failure in Caucasian population. To investigate the distribution of the two genetic defects in Chinese patients with azoospermia or severe oligozoospermia, karyotype analysis by G-banding was carried out in 358 idiopathic infertile men, including 256 patients with azoospermia and 102 patients with severe oligozoospermia, and screening of AZF region microdeletion of Y chromosome by multiplex PCR was performed in those patients without detectable chromosomal abnormality and 100 fertile controls. Of 358 patients, 39(10.9%) were found to have chromosomal abnormalities in which Klinefelters syndrome (47, XXY) was the most common chromosomal aberration. The incidence of sex chromosomal abnormality in patients with azoospermia was significantly higher than that in patients with severe oligozoospermia (12.1% vs 1%). Among the rest of the 319 patients with normal karyotype, 46 (14.4%) were found to have microdeletions in AZF region. The prevalence rates of AZF microdeletion was 15% and 13.1% in patients with azoospermia and severe oligozoospermia respectively. The microdeletion in AZFc was the most frequent deletion and all the microdeletions in AZFa were found in azoospermic patients. No microdeletion in AZF region was detected in fertile controls. In conclusion, chromosomal abnormality and AZF region microdeletion of Y chromosome might account for about 25% of Chinese infertile patients with azoospermia or severe oligozoospermia, suggesting the two abnormalities are important genetic etiology of spematogenic failure in Chinese population and it is essential to screen them during diagnosis of male infertility before in vitro assisted fertilization by introcytoplasmic sperm injection.     

中国无精症、严重寡精症患者的染色体异常和Y染色体微缺失

染色体异常和Y染色体微缺失被认为是两个白种人群中常见的生精障碍相关遗传因素。为了解中国无精症、严重寡精症患者中的染色体异常和Y染色体微缺失,运用染色体G显带技术,在358个原发无精症（256人）和严重寡精症（102人）不育患者中进行染色体核型分析;同时运用多重PCR技术,在核型正常的患者和100个正常生育男性中,对Y染色体AZF区微缺失进行筛查。在358个患者中,39人（10．9％）发现有染色体异常,Klinefelter（47,XYY）最为常见。无精症患者性染色体异常频率明显高于严重寡精症患者（12．1％VS1％）。在319个核型正常的患者中,46（14．4％）发现有AZF区微缺失,无精症和寡精症患者中Y染色体微缺失频率分别为15％和13．1％,AZFc区的微缺失最为常见,AZFa区的微缺失只见于无精症患者,正常生育男性中未发现AZF区的微缺失。结果显示,在中国无精症、严重寡精症患者中,大约25％的患者有染色体异常或Y染色体AZF区微缺失,提示这两种遗传异常是中国人群生精障碍的重要相关遗传病因,有必要在男性不育的诊断以及利用细胞浆内精子注射技术进行辅助生育时,对患者的这些遗传异常进行筛查。     

The mystery of chromosomal translocations in cancer

Chromosomal translocations in human cancer may result in products that can be suppressed by targeting drugs. An example is bcr-abl tyrosine kinase in chronic myelogenous leukemia that can be treated with imatinib mesylate. However, the mechanisms of translocations or exchanges of chromosomal segments are virtually unknown. In this summary, chromosomal translocations in human cancer are compared with 'crossing over' of chromosomal segments occurring during the first meiotic division. Several proposed mechanisms of the exchange of DNA between and among chromosomes are discussed. The conditions that appear essential for these events to occur are listed. Among them are proximity of the involved DNA segments, mechanisms of excising the target DNA, its transport to the new location, and integration into the pre-existing chromosome. The conclusion based on extensive review of the literature is that practically nothing is known about the mechanism of 'crossing over' or translocation. Based on prior work on normal human cells, it is suggested that only one of the two autosomes participates in these events that may include loss of heterozygozity, another common abnormality in human cancer.     

Masked complex chromosome rearrangement in a child thought to have del(8qter) as the sole cytogenetic abnormality

Cytogenetic analyses of constitutional diseases have disclosed several chromosomal rearrangements. At the molecular level, these rearrangements often result in the breakage of genes or alteration of genome architecture. Fluorescence in situ hybridization (FISH) and molecular investigations of a patient showing hypotonia and dysmorphic traits revealed a masked complex chromosome abnormality previously detected by G-banding as a simple 8qter deletion. To characterize the genetic rearrangements panels of bacterial artificial chromosomes (BACs) covering 8q24.22-->qter were constructed, and short tandem repeats (STRs) were used to refine the localization of the breakpoints and to assess the parental origin of the defect. Chromosome 8 displayed the breakpoint at 8q24.22 and an unexpected distal breakpoint at 8q24.23 resulting in unbalanced translocation of a small 8q genomic region on the chromosome 16qter. The study of the 16qter region revealed that the 16q subtelomere was retained and the translocated material of distal 8q was juxtaposed. Moreover, molecular analyses showed that part of the translocated 8qter segment on der(16) was partially duplicated, inverted and that the rearrangement arose in the paternal meiosis. These findings emphasize the complexity of some only apparently simple chromosomal rearrangements and suggest a subtelomeric FISH approach to enhance diagnostic care when a cytogenetic terminal deletion is found.     

Evidence for high frequency of chromosomal mosaicism in spontaneous abortions revealed by interphase FISH analysis.

Numerical chromosomal imbalances are a common feature of spontaneous abortions. However, the incidence of mosaic forms of chromosomal abnormalities has not been evaluated. We have applied interphase multicolor fluorescence in situ hybridization using original DNA probes for chromosomes 1, 9, 13, 14, 15, 16, 18, 21, 22, X, and Y to study chromosomal abnormalities in 148 specimens of spontaneous abortions. We have detected chromosomal abnormalities in 89/148 (60.1%) of specimens. Among them, aneuploidy was detected in 74 samples (83.1%). In the remaining samples, polyploidy was detected. The mosaic forms of chromosome abnormality, including autosomal and sex chromosomal aneuploidies and polyploidy (31 and 12 cases, respectively), were observed in 43/89 (48.3%) of specimens. The most frequent mosaic form of aneuploidy was related to chromosome X (19 cases). The frequency of mosaic forms of chromosomal abnormalities in samples with male chromosomal complement was 50% (16/32 chromosomally abnormal), and in samples with female chromosomal complement, it was 47.4% (27/57 chromosomally abnormal). The present study demonstrates that the postzygotic or mitotic errors leading to chromosomal mosaicism in spontaneous abortions are more frequent than previously suspected. Chromosomal mosaicism may contribute significantly to both pregnancy complications and spontaneous fetal loss.