五条常染色体复杂易位核型一例

孕妇女,29岁,孕1产0.平素月经规则.此次妊娠孕20周行中孕期唐氏综合征筛查为21三体高风险,故在我院行羊水细胞产前诊断.羊水细胞染色体核型分析结果:计数30个核型,分析其中5个核型,胎儿核型为46,XX,t(3;5;9;14;8)(3pter→3q27::8q21.1→8qter:5pter→5q31::3q27→3qter;9pter→9q13::5q31→5qter;14pter→14q24::9q13→9qter;8pter →8q21.1::14q24→14qter),复查脐带血结果一致,见图1.孕23周三维B超检查未见胎儿明显异常.孕妇及其丈夫外周血细胞染色体核型正常.孕妇夫妇否认致畸因子接触史.该孕妇于孕39周足月产下一女婴,未见异常表型.     

染色体结构异常世界首报二例

病例: 例1:患者,女,23岁, 因2次不良孕产史就诊.第1胎孕29w,B超示胎儿多发畸形行引产术,第2胎孕17w,B超示"胎儿脑脊膜膨出,胸腔积液"行引产术.染色体G显带分析10个分裂相,其核型为:46,XX,ins(5;2)(5pter→5q13::2q31→2q23::5q13→5qter;2pter→2q23::2q31→2qter),t(8;13)(8qter→8p23::13q22→13qter;13pter→13q22::8p23→8pter) .(图①)其夫核型正常.     

以十二指肠梗阻为产前表现的17q12微重复综合征2例

27岁, G1P0, 平素月经规则, 无出血及其他不适, 无胎儿畸形家族史。孕22周超声显示宫内妊娠, 单活胎, 十二指肠梗阻可能(图1);颈项透明层超声和孕中期唐氏综合征筛查均为低风险。孕24周G显带核型分析显示胎儿核型为46, XN, inv(9)(p11q13);染色体微阵列分析(chromosomal microarray analysis, CMA)结果显示为arr[GRCh37]17q12(34440088₃6351919)×3(图3), 提示胎儿染色体17q12区存在1.912 Mb重复。抽取夫妇双方外周血样进行CMA验证:孕妇1未见异常, 其丈夫为arr[GRCh37]17q12(34440088₃6350028)×3(图4), 提示胎儿的染色体重复遗传自父亲。     

同时携带平衡易位和罗氏易位衍生染色体的胎儿一例

孕妇 29岁, 孕1产0, 因丈夫同时携带染色体平衡易位和罗氏易位行胚胎植入前结构重排遗传学检测(preimplantation genetic testing: structural rearrangement, PGT-SR)。植入未见染色体拷贝数异常的胚胎后, 于孕20周就诊于我院。本研究通过了我院伦理委员会审查(202201247)。在签署知情同意书后, 常规进行羊膜腔穿刺, 抽取羊水分别进行细胞原位培养和单核苷酸多态性微阵列分析(single nucleotide polymorphism array, SNP-array)。胎儿SNP-array分析未见明显异常。羊水细胞G显带分析提示胎儿为平衡易位合并罗氏易位衍生染色体携带者。其母亲核型未见异常, 父亲为45, XY, t(3;13)(q26.2;q21.3), der(13;14)(q10;q10)(图1)。胎儿的染色体核型如图2所示, 结合其父亲的染色体核型, 根据2020版人类细胞基因组学国际命名体制(International System for Human Cytogenetic Nomenc, ISCN 2...     

染色体核型异常14例

例1 男,27岁.其妻孕19周B超显示胎儿脐膨出而引产.患者染色体核型为46,XY,inv(3)(p14q13).其妻核型正常.     

inv(11)(q13q21)伴习惯性流产一例

患者　女,32岁,已婚。第1胎孕7个月时B超检查发现胎儿生长发育迟缓,胎心消失而行引产。第2胎孕3个月,第3胎孕1个月,均自然流产。患者非近亲结婚,表型正常。其父母及两兄弟一姐一妹生育均正常,无流产史。细胞遗传学检查:取外周血淋巴细胞培养,制片,染色体G显带,分析20个中期分裂相,核型为46,XX,inv(11)(q13q21)(pter→q13∷q21→q21∷q13→qter。丈夫核型46,XY。讨论　本例为罕见的11号染色体长臂臂内倒位携带者。臂内倒位携带者其本身因没有重要遗传物质的丢失或增多,故外表无异常,但此倒位可能是造成其胎儿生长发育异常、死亡及流产的原…     

罕见异常核型家系分析

<正>病例:先证者为孕18周胎儿。因孕期产前唐筛为高风险而做羊水细胞遗传学检查。结果:胎儿羊水染色体核型为:46,XX,der(10)(10pter→10q26∷4q25→4qter),见图1。胎儿母亲核型正常,父亲核型为46,XY,t(4;10)(q25;q26),说明该胎儿异常染色体来源于父亲。为查异常染色体来源,本文做了详细家系调查并对其他     

罗伯逊易位一家系

先证者(Ⅲ1) 男,5岁,生后5个月时发现发育各项指标较同龄人均晚,就诊于当地医院.查体:眼距宽,外眼角上斜,耳位较低,鼻梁扁平,双手通贯掌,心肺功能正常;在当地医院查染色体核型为:46,XY,+21,der(13;14)(q10;q10),16qh+.家系调查(图1):先证者母亲,29岁,表型正常.染色体核型为46,XX,16qh+.此后,以节育器避孕,取环后2个月即怀孕,孕19周就诊,行羊膜腔穿刺取羊水做胎儿染色体核型分析,细胞遗传学检查胎儿染色体核型为45,XX,der(13;14)(q10;q10).随访:足月顺产一女婴,发育及外观正常.     

产前诊断46,XX,t(8;16)(q22;q22)一例CSCD

孕妇29岁,G_(1)P_(0),否认家族遗传病史。孕25^(+)周胎儿系统超声提示胎儿右锁骨下动脉迷走(图1)。经夫妻双方签署知情同意书后在我院行羊膜腔穿刺术。细胞遗传学检查;常规羊水细胞培养,染色体制备,G显带,计数20个分裂相,分析5个核型,羊水胎儿染色体核型为:46,XX,t(8;16)(q22;q22)(图2)。胎儿母亲染色体核型未见异常。     

染色体平衡易位六例及其家系调查

例1 男,36岁.其妻4次自然流产,均于妊娠70天左右.第5次妊娠18周,B超提示胎儿脐膨出.在我院产前诊断中心行羊膜腔穿刺,检测胎儿染色体核型为:46,XY,-18,+t(3;18)(q22;p11).本次妊娠孕25周再次检测B超提示:羊水过多,胎儿脐膨出,先天性心脏畸形(室间隔缺损,主动脉狭窄),Dandywalker畸形,侧脑室轻度扩张等多发畸形,于孕28周引产.患者表型、智力正常,无有害物接触史.非近亲婚配.患者夫妇外周血染色体核型分析,患者核型为:46,XY,t(3;18)(q23;p11).     

Constitutional mosaicism for a chromosome 9 inversion resulting in recombinant aneusomy in an offspring

We report on a case of constitutional mosaicism for a large pericentric inversion of chromosome 9 in a man whose daughter had recombinant aneusomy resulting in partial 9q duplication and partial 9p deletion. At age 6 months, the girl was evaluated because of dysmorphic congenital animal features and developmental delay. Chromosomal analysis on this infant showed a derivative chromosome 9 which was later determined to be a recombinant chromosome with trisomy of 9q34.1→qter and monosomy of pter→9p24. Chromosomal analysis in her father showed the presence of two cell lines; 75% of lymphocytes had a 46,XY pattern, and 25% had a 46,XY,inv(9)(p24q34.1) karyotype. The infant's physical findings represent a composite of the reported cases of both trisomy 9q34.1→qter and monosomy pter→9p24. The infant's father was phenotypically and cognitively normal. This case broadens the spectrum of reported cases of mosaicism for an autosomal structural rearrangement generating unbalanced gametes, and further supports the tenet that constitutional mosaicism has clinical relevance for genetic counseling. Am. J. Med. Genet. 69:360–364, 1997. © 1997 Wiley-Liss, Inc.     

Tandem duplication mosaicism: characterization of a mosaic dup(5q) and review

Mosaicism for tandem duplications is rare. Most patients reported had abnormal phenotypes of varying severity, depending on the chromosomal imbalance involved and the level of mosaicism. Post-zygotic unequal sister-chromatid exchange has been proposed as the main mechanism for tandem duplication mosaicism. However, previous molecular analyses have implicated both meiotic and post-zygotic origins for the duplication. We describe a newborn male who was originally diagnosed in utero with arrhythmia and tetralogy of Fallot. He had multiple dysmorphic features including telecanthus, blepharophimosis, high broad nasal bridge with a square-shaped nose, flat philtrum, thin upper lip, down-turned corners of the mouth, high-arched palate, micrognathia, asymmetric ears, and long, thin fingers and toes. Karyotyping of peripheral blood lymphocytes showed mosaicism for a tandem duplication of part of the long arm of one chromosome 5: mos46,XY,dup(5)(q13q33)[6]/46,XY[45]. Fibroblast cultures had the same mosaic karyotype with a higher frequency of the dup(5) clone: mos46,XY,dup(5)(q13q33)[9]/46,XY[21]. Fluorescence in situ hybridization analysis with a wcp5 confirmed the chromosome 5 origin of the additional material. Parental karyotypes were normal indicating a de novo origin of the dup(5) in the proband. Molecular analyses of chromosome 5 sequence-tagged-site (STS) markers in our family were consistent with a post-zygotic origin for the duplication. Therefore, mosaicism for tandem duplications can arise both through meiotic or mitotic errors, as a result of unequal crossing over or unequal sister-chromatid exchange, respectively. Our review indicates that mosaicism for tandem duplications is likely under-ascertained and that parental karyotyping of probands with non-mosaic tandem duplications should be performed.     

Pseudo dicentric chromosome (5;21): a rare example of maternal germline mosaicism

Karyotyping of a malformed male newborn revealed the unbalanced karyotype of 46,XY, psudic(5;21)(q12;p13), +5 resulting in trisomy for the short arm of chromosome 5 and partial trisomy for 5q. Both parents had normal karyotypes in their peripheral blood lymphocytes. A second pregnancy ended in a miscarriage at 16 weeks gestation, sonographically 12 weeks. Karyotyping of chorionic villi from the abortus revealed the same unbalanced karyotype that had been identified in the first child. Fluorescence in-situ hybridization analysis confirmed a trisomy 5p. Microsatellite marker analysis ruled out illegitimacy and proved the maternal origin of the trisomic section of chromosome 5. Extended chromosome analysis of 60 metaphase cells from maternal skin fibroblasts and 40 metaphase cells from lymphocytes did not reveal mosaicism for psudic(5;21). These findings suggest the presence of a maternal germline mosaicism.     

Cryptic duplication of 12q24.33 --> qter in a child with Angelman syndrome-simultaneous occurrence of two unrelated cytogenetic events

Simultaneous occurrence of two unrelated cytogenetic events is rare. We present a case of Angelman Syndrome (AS) deletion and 12q duplication in a child with a history of developmental delay, microcephaly, cerebral palsy, and seizures. Traditional cytogenetic studies showed a normal 46,XY karyotype. Fluorescence in situ hybridization (FISH) using probe D15S10 (AS region/15q11.2) revealed a deletion. In addition, we serendipitously detected 12q24.3 duplication by FISH with 12q subtelomere probe. He inherited this duplication from the mother who presented with a balanced translocation karyotype 46,XX,add(12)(q24.3).ish t(12;13)(q24.3;p11.2)(12qtel-;12qtel+,D13Z1/D21Z1+,RB1+). Array comparative genomic hybridization (array-CGH) revealed a duplication of three bacterial artificial chromosome (BAC) clones (RP11-46H11, RP11-386I8, and RP11-309H3) covering about 423 Kb of DNA sequence. The published 12q terminal duplication cases had a detectable segment by classical banded cytogenetics techniques. To our knowledge, this is the smallest 12q cryptic rearrangement characterized by array-CGH and confirmed by BAC-clone FISH analysis. Based on these findings, we attempted to separate the clinical features associated with AS deletion and those features that are probably due to partial 12q duplication. We then reviewed the genes mapped in the duplicated region using the human genome database to understand the clinical significance. A subsequent pregnancy in the mother revealed an apparently balanced t(12;13) karyotype. We compare our case with the published cases, and discuss the implications of our findings and its relevance in addressing genetic counseling issues.     

Tetrasomy 13q31.1qter due to an inverted duplicated neocentric marker chromosome in a fetus with multiple malformations

Small supernumerary marker chromosome (sSMC) lacking alpha satellite DNA or endogenous centromere regions are rare and contain fully functional centromeres, called neocentromeres. We report on a woman with a 14-week gestation pregnancy with a cystic hygroma and cerebellar hypoplasia at ultrasound examination. Cytogenetic studies showed a karyotype 47,XY,+mar dn. This sSMC was observed in chorionic villi, lung, and muscle tissue. Array Comparative Genomic Hybridization showed a gain from 13q31.1 to 13qter region. Fluorescent in situ hybridization with pan alpha satellite probe and probes specific for chromosome 13 showed a marker corresponding to an inversion duplication of the 13q distal chromosomal region without alpha satellite DNA sequence, suggesting the presence of a neocentromere. Examination of the fetus showed dysmorphic features, cystic cervical hygroma, postaxial polydactyly of the right hand and left foot with short fingers, malrotation of the gut, and a micropenis with hypospadias. Genotype-phenotype correlation in tetrasomy 13q is discussed according to the four 13q chromosomal breakpoints reported (13q32, 13q31, 13q21, 13q14) for chromosome 13 supernumerary markers.     

Significance of a prenatally diagnosed del(10)(q23).

Structural chromosome mosaicism is rare. We report a case of prenatal mosaicism for a deletion of chromosome 10(q23). To our knowledge, there are only three reports of prenatally diagnosed cases of del(10)(q23). Two of these cases were due to an inherited fragile site. In the present case amniocentesis revealed 46,XY,del(10)(q23)[9]/46,XY[45]. Follow-up chromosome analysis of peripheral blood and placental tissue from a phenotypically normal liveborn male revealed the del(10)(q23) in only 3/100 blood cells grown in low-folate medium. It appears that prenatally diagnosed deleted (10q) mosaicism represents culture artifact and is not clinically significant.     

Prenatal diagnosis of congenital diaphragmatic hernia in a fetus with 46,XY/46,X,-Y,+der(Y)t(Y;1)(q12;q12) mosaicism: a case report

Congenital diaphragmatic hernia (CDH) is often associated with major anomalies and chromosomal abnormalities. Chromosomal abnormalities are usually detected in 9.5% to 34% of fetuses with CDH prenatally diagnosed and the defect has also been reported in association with multiple syndromes such as Pallister-Killian syndrome, Fryns syndrome, Di George syndrome and Apert syndrome. Among the chromosomal abnormalities associated with CDH, trisomy 21, 18, and 13 are most common. Association with complex chromosomal aberrations such as mosaicism has also been reported. However, CDH presented in a fetus with Y-autosome translocation is extremely rare. Herein, we reported a case of fetus with 46,XY/46,X,-Y, +der(Y)t(Y;1)(q12;q12) mosaicism who presented with CDH diagnosed by ultrasonography at 19 weeks' gestation.     

7号染色体臂间倒位伴Turner综合征家系分析

目的研究7号染色体臂间倒位的遗传机制。方法患儿及父母作染色体检查,并对患儿的家系进行调查。结果患儿的染色体核型为46,XX,inv(7)(p22q11)/45,X,inv(7)(p22q11),其中46,XX,inv(7)(p22q11),85%,45,X,inv(7)(p22q11),15%。父亲的核型为46,XY,inv(7)(p22q11),母亲的染色体正常,患儿的母亲第1胎为3月自然流产,家系中其它成员均无流产史,母系成员中身材均偏矮小。结论染色体臂间倒位能引起流产和畸胎,应作产前诊断。     

Fetal t(5p;21q) misdiagnosed as monosomy 21: A plea for in situ hybridization studies

We report a case of 45,XY,?5,?21,+der (5) t(5;21) (p13 or p14;q11.2 or q21) that was prenatally misdiagnosed as complete monosomy 21 and terminated at 24 weeks of gestation. Subsequent fluorescence in situ hybridization studies with a chromosome 21 painting probe documented the cryptic unbalanced translocation. © 1994 Wiley-Liss, Inc.     

Significance of a prenatally diagnosed del(10)(q23)

Structural chromosome mosaicism is rare. We report a case of prenatal mosaicism for a deletion of chromosome 10(q23). To our knowledge, there are only three reports of prenatally diagnosed cases of del(10)(q23). Two of these cases were due to an inherited fragile site. In the present case amniocentesis revealed 46,XY,del(10)(q23)[9]/46,XY[45]. Follow‐up chromosome analysis of peripheral blood and placental tissue from a phenotypically normal liveborn male revealed the del(10)(q23) in only 3/100 blood cells grown in low‐folate medium. It appears that prenatally diagnosed deleted (10q) mosaicism represents culture artifact and is not clinically significant. © 2002 Wiley‐Liss, Inc.