67例妊娠晚期胎儿生长受限的遗传学因素探讨

目的探讨单核苷酸多态性微阵列芯片技术(single nucleotide polymorphism array,SNP-array)在胎儿生长受限的遗传学病因的应用价值。方法回顾性分析67例妊娠晚期因胎儿生长受限行介入性产前诊断取脐带血标本染色体核型分析与染色体微阵列芯片检测情况。采用Illumina Human Cyto SNP12微阵列芯片进行全基因组拷贝数变异(copy number variations, CNVs)检测,结合查询国际病理性CNVs数据库、正常人基因组变异数据库(database of genomic variants, DGV)及PubMed文献数据库等对检出的CNVs的致病性进行分析。结果67例胎儿脐带血染色体核型异常6例,检出率8.96%(6/67),其中1例21-三体综合征,2例18-三体综合征,1例染色体缺失,1例衍生染色体,1例染色体倒位;SNP-array检出11例异常,检出率16.42%(11/67)。11例芯片异常中有7例致病性,1例疑似致病性,其余3例为临床意义不明。结论妊娠晚期胎儿生长受限胎儿行SNP-array检测有助于发现染色体核型分析无法检出的染色体亚显微结构异常,提高其遗传病因的诊断。     

Pierre Robin序列征1例报告

Pierre Robin序列征（Pierre Robin sequence,PRS）既往称为Pierre Robin综合征、小下颌-舌后坠综合征及下颌退缩症[1]。临床较罕见,大多为个案报道,本病的死亡率高,婴儿的早期死亡率可达30%~60%[2]。早期发现PRS,对改善该病患儿预后和提高生存质量具有重要意义。笔者收治1例本病患儿报道如下,以提高临床医生对本病的认识。1病例资料患儿,男,17个月。因＂发热2d＂于2014-02-22入院。     

染色体微阵列芯片分析技术在精神运动发育迟缓患儿中的应用价值

目的应用染色体微阵列芯片分析技术对150例不明原因的精神运动发育迟缓)患儿进行拷贝数变异(CNV)检测,探讨其基因遗传病因。方法收集2015年1月至2019年6月我科精神运动发育迟缓患儿150例,采用Affymetrix CytoScan 750K芯片进行基因组学分析。结果 25例患儿携带与MR/DD相关的CNVs,检出率达16.7%(25/150)。其中10例为已知综合征患者,微缺失2例,大片段缺失1例,临床致病性拷贝数改变7例,临床意义不明5例。结论染色体微阵列芯片分析技术可以提高对不明原因精神运动发育迟缓患儿的分子病因诊断水平,对深入研究病因机制有重要意义,为患儿预后、康复决策制定、家庭再发风险评估提供指导。     

染色体微阵列技术在产前诊断中的应用

近年来,染色体微阵列技术(chromosomal microarray analysis,CMA,又称为基因芯片技术),由于具有容量大、高自动化、大规模效应而逐渐被应用到产前诊断中,为产前诊断提供了新的途径,其在对染色体拷贝数异常(copy number variation,CNVs)即染色体的数目异常、片段缺失和重复的检测方面比传统的染色体核型分析具有明显的优越性. 1 CMA的特点及进展 染色体微阵列技术(CMA),也叫分子核型分析技术(molecular karyotyping),代表所有以微阵列为技术基础的基因组拷贝数分析技术,包括基于比较基因组杂交的微阵列(array-based comparative genomic hybridization,aCGH)和基于单核苷酸多态性的微阵列(single nucleotide polymorphism arrays,SNP arrays)o aCGH是最先发展、也是目前仍然最为广泛应用的微阵列技术.其次是SNP arrays技术,它在对人类基因组变异检测的基础上增加了单核苷酸多态性的信息数据.但以细菌人工染色体BAC(bacterial artificial chromosomes,BACs)为探针的aCGH的缺点之一是它无法对小于其探针长度即100～150 kb的CNVs进行检测,而且,它容易造成对CNVs片段长度的高估,例如CNV仅占BAC探针长度的50％,而检测时系统会误认为CNVs覆盖了BAC探针全长.     

产前诊断Angelman综合征1例

优生优育日益受到国家、社会和家庭的高度重视和关注,近年高龄孕妇在孕妇的结构中占比较以前提高18%左右,而外周血无创DNA检测技术(non-invasive prenatal testing,NIPT)应用突飞猛进,并在临床“广泛”开展,1例NIPT阴性高龄孕妇,经产前诊断羊水细胞培养进行染色体核型分析和全基因组芯片分析确诊:46,XN,15q11.2-q1413.8Mb Del天使综合征(Angelman syndrome,AS),暨母源性15q11.2-q14的缺失。     

无创产前检测胎儿染色体拷贝数变异的临床价值初探

目的探讨无创产前检测(NIPT)对筛查胎儿染色体拷贝数变异(CNVs)和微缺失/微重复综合征(MDs)的临床价值。方法收集2012年1月至2017年7月在云南省第一人民医院遗传诊断中心、产前诊断中心10 005例中孕期(15～20+6周)进行NIPT的孕妇资料,对检测提示胎儿CNVs孕妇中选择介入性产前诊断者的羊水/脐血染色体G显带核型分析及高通量测序(NGS)基因组拷贝数分析,相关CNVs到相应数据库查找分析,分析NIPT所发现的CNVs与介入性产前诊断结果的一致性。结果中孕期进行NIPT的10 005例孕妇中提示胎儿CNVs 32例,筛查阳性率为0.32%(32/10 005)。知情同意接受介入性产前诊断25例,其中确诊胎儿CNVs14例,阳性预测值(PPV)为56%(14/25),包括微缺失9例、微重复5例,片段大小在587.75kb～36.05Mb之间。胎儿细胞DNA样本NGS检测到的片段大小和起止位置与NIPT筛查时所见CNVs基本吻合。在14例CNVs中确诊MDs 11例,临床意义不明CNVs 3例。对11例MDs胎儿的父母亲进行CNVs检测和外周血染色体核型分析,证实新发病CNVs 10例,其中父系染色体异常来源致病CNVs 2例;8例致病CNVs胎儿合并有染色体结构异常。经遗传咨询,这11例致病变异有10例夫妇知情选择终止妊娠;1例知情选择继续妊娠,分娩1例活产新生儿。结论 NIPT作为一种高精度筛查手段,能够筛查出部分有临床意义的胎儿CNVs,可望成为常规筛查手段,检测致病风险大的较大片段的染色体微缺失和微重复CNVs(≥5Mb);NIPT检测到胎儿CNVs高风险时需进行介入性产前诊断。     

7p部分三体综合征的表型和基因型关系研究

目的:探讨7p部分三体综合征的起源,分析患者表型和基因型的关联性,同时研究单核苷酸多态-微阵列比较基因组杂交技术(SNP aCGH)在检测亚细胞遗传学改变中的应用价值。方法:对外院核型报告正常的1例特殊面容、低智合并先心患儿复查染色体,G带发现其4q35.2区域疑似有额外片断附着,进一步用SNP aCGH进行全基因组扫描,并用4号染色体长臂末端和7号染色体短臂末端探针与患儿淋巴细胞杂交(FISH)以验证SNP aCGH结果,同时对患儿进行家系调查及部分成员染色体检查。结果:患儿核型46,XX,add(4)(q35.2)?全基因组扫描显示,患儿7p21.1-pter区域有20.78Mb的重复,而4q35.2-qter区域有3.24Mb的缺失。FISH发现,患儿外周血淋巴细胞含3个拷贝的7号染色体短臂末端和1个拷贝的4号染色体长臂末端。家系调查发现,患儿父亲及祖父均为46,XY,t(4;7)(q35.2;p21.1)。综合以上结果,确定患儿核型为46,XX,der(4)t(4;7)(q35.2;p21.1)pat,异常核型由父亲传递,系精子在减数分裂中通过邻近分离-I所形成的不平衡产物。患儿不平衡片断包含与颅骨发育异常相关的TWIST基因、与先心相关的MOX2基因以及与颅面部异常特征相关的ACTB基因。结论:亲代平衡易位导致的子代小片断不平衡是7p部分三体综合征等出生缺陷的重要原因;SNP aCGH是鉴别小片断不平衡的有效手段;7p部分三体综合征患者异常表型可能与TWIST、MOX2、ACTB等基因有关。     

5p15缺失综合征合并4q32重复1例临床分析与基因诊断

目的 探讨5p15缺失综合征合并4q32重复的临床特征及分子遗传学特点.方法 回顾分析1例5p15缺失综合征合并4q32重复患儿的临床资料以及分子遗传学分析资料.结果 10月龄女性患儿,具有特殊面容、发育迟缓、先天性心脏病及喉软骨发育不良等临床表现.全外显子测序和染色体组拷贝数分析精确定位拷贝数异常改变的染色体片段区域...     

拷贝数变异的报告解读技术标准的联合共识

美国医学遗传学与基因组学学会及临床基因组资源中心于2019年11月6日发布了“原发性拷贝数变异的报告解读技术标准的联合共识”,现将核心内容整理如下一、主要更新要点1.拷贝数变异(copy number variations,CNVs)分类借鉴“ACMG/AMP基W序列变异解读指南”更新为五分类法。     

不同受精方式早期自然流产物染色体异常分析

目的探讨不同受精方式对临床早期自然流产组织的染色体异常分布的影响。方法回顾性分析102例早期流产患者的临床资料,应用微阵列比较基因组杂交技术(array-based comparative genomic hybridization,a CGH)比较体外受精(IVF)组(35例)、卵胞质内单精子注射(ICSI)组(31例)、对照组(自然妊娠及夫精人工授精组,36例)流产组织染色体异常率及拷贝数变异(copy number variants,CNVs)。结果流产组织染色体异常率3组间比较差异无显著统计学意义,其中三倍体最常见,其次为微重复/微缺失、单体等。IVF/ICSI微刺激促排卵患者流产组织核型异常比例最高,随着流产次数增加,正常核型胚胎比例增加。共检测出20个CNVs,9个CNVs为基因组微重复,11个CNVs为基因组微缺失。结论不同受精方式不影响其自然流产妊娠物染色体异常率及异常分布,有意义的CNVs及其包含的流产相关候选基因将为进一步揭示自然流产原因提供研究方向。     

Prenatal diagnosis and molecular cytogenetic characterization of a chromosome 1q42.3-q44 deletion in a fetus associated with ventriculomegaly on prenatal ultrasound

ObjectiveWe present prenatal diagnosis and molecular cytogenetic characterization of a chromosome 1q42.3-q44 deletion in a fetus associated with ventriculomegaly on prenatal ultrasound, and we discuss the genotype–phenotype correlation.Case reportA 36-year-old woman underwent amniocentesis at 17 weeks of gestation because of advanced maternal age. Amniocentesis revealed a karyotype of 46,XX,del(1) (q42.3q44). Simultaneous array comparative genomic hybridization analysis on uncultured amniocytes revealed arr 1q42.3q44 (234,747,397–246,081,267) × 1 [GRCh37 (hg19)] with an 11.33-Mb 1q42.3-q44 deletion encompassing RGS7, FH, CEP170, AKT3, ZBTB18 and HNRNPU. The parental karyotypes were normal. Prenatal ultrasound at 20 weeks of gestation revealed bilateral ventriculomegaly and dilation of the third ventricle. The pregnancy was subsequently terminated, and a malformed female fetus was delivered with characteristic facial dysmorphism. Postnatal conventional and molecular cytogenetic analyses confirmed the prenatal diagnosis. Polymorphic DNA marker analysis showed a paternal origin of the distal 1q deletion in the fetus.ConclusionFetuses with a chromosome 1q42.3-q44 deletion may present ventriculomegaly on prenatal ultrasound. Prenatal diagnosis of ventriculomegaly should include a differential diagnosis of chromosome 1q distal deletions, and aCGH is useful under such a circumstance.     

Interstitial deletion del(10)(q25.2q25.3 approximately 26.11)--case report and review of the literature

OBJECTIVES: To present the clinical, cytogenetic, and molecular cytogenetic findings of prenatally diagnosed interstitial deletion 10q25.2-q26.1. The majority of distal 10q deletions are pure terminal deletions with breakpoints in 10q25 and 10q26. Only four patients have been described so far with interstitial deletions involving bands 10q25.2-q26.1. METHODS: Postmortem physical examination and autopsy of the foetus after medically terminated pregnancy. GTG-banding, reverse painting, and FISH analysis with BAC clones on amniocyte metaphases were performed to determine the extent of the deletion. RESULTS: At 20 weeks the eutrophic female foetus showed pronounced microretrogeny and hypertelorism, clubfeet as well as minor internal anomalies like pancreas anulare, atypically lobed liver, and missing choleocystis. Cardiac anomalies were not observed and the genitalia were of a normal female. The deletion encompasses 6-Mb and is associated with hemizygosity for 30 genes, including the genes for beta-tectorin, the beta-1 adrenergic receptor, and the alpha-2A adrenergic receptor. CONCLUSION: An interstitial deletion del(10)(q25.2q25.3 approximately 26.11) was confirmed by FISH with mapped BAC clones. Clinical and molecular cytogenetic analyses of further interstitial 10q deletions are necessary to assess whether the phenotypic manifestations differ between deletions that are interstitial compared to those that include also the terminal region of chromosome 10.     

Relatively mild phenotype in a patient with interstitial 6q24.3-q25.2 deletion

We report a patient with a de-novo interstitial deletion of chromosome 6 with breakpoints at q24.3-q25.2. The patient presented with intra-abdominal testes, mild dysmorphic features, feeding difficulties in the first 3 years of life and normal development with no learning difficulties. To our knowledge this is the first report of a 6q interstitial deletion with these particular breakpoints. This is also the first patient with an interstitial 6q deletion and normal intellectual development. Cryptorchidism seems to be a recurrent finding in males with 6q deletions involving similar breakpoints.     

Allelic deletion mapping on chromosome 6q and X chromosome inactivation clonality patterns in cervical intraepithelial neoplasia and invasive carcinoma

OBJECTIVE: Loss of heterozygosity (LOH) profiles and X chromosome inactivation patterns are analyzed in 42 patients with cervical intraepithelial neoplasias (CIN), including low-grade (CIN1) and high-grade (CIN2, CIN3) lesions, and 22 patients with invasive cervical carcinomas. METHOD: Laser capture microdissection was utilized to procure pure matched normal and lesional cells from each case. Sixteen microsatellite markers on four chromosomal arms, 6q21-q25.1, 8p21, 13q12.3--q13, and 17q12--q21, were amplified for LOH, as well as the HUMARA locus for X chromosome inactivation analysis. Eight additional markers spanning the long arm of chromosome 6 were utilized in all cases showing LOH on this arm and in which further tissue material was available for microdissection. RESULTS: Fifty-five percent of carcinomas showed deletions on chromosome bands 6q21--q25.1, 43% on 13q12.3--q13, and 40% on 17q12--q21. Deletions on 6q were identified in CIN3 (40%), CIN2 (37%), and CIN1 (10%), on 13q in CIN3 (33%) and CIN2 (33%), and rarely on chromosomal arm 17q. Finer 6q mapping revealed that marker D6S310 (q22) represented the centromeric and marker D6S255 (q25--q16) the telomeric boundary of deletion. A second, telomeric area of deletion at marker D6S281 (q27) was also identified. Monoclonal X chromosome inactivation patterns were identified in 12/13 cancers, 13/14 CIN3, 5/10 CIN2, and 0/6 CIN1. CONCLUSIONS: Two areas of deletion on chromosome 6q were identified in cervical tumors, suggesting the presence of tumor suppressor gene(s) inactivated in this neoplasia. LOH on this arm were identified early during cervical tumor progression. LOH on 13q and 17q also occur in cervical cancers. X chromosome inactivation patterns suggest that CIN develops into a monoclonal lesion during progression from CIN1 to CIN3.     

Prenatal diagnosis and molecular cytogenetic characterization of a de novo interstitial duplication of 14q (14q31.3→q32.12) associated with abnormal maternal serum biochemistry

ObjectiveTo present prenatal diagnosis and molecular cytogenetic characterization of a de novo interstitial duplication of 14q (14q31.3→q32.12) in a pregnancy associated with abnormal maternal serum biochemistry.Case ReportA 19-year-old woman underwent amniocentesis in the second trimester because of abnormal maternal serum biochemistry. Her husband was 33 years old. At 16 weeks of gestation, the levels of α-fetoprotein, unconjugated estriol, total β-human chorionic gonadotropin, and inhibin A were 0.8 multiples of median (MoM), 0.84 MoM, 3.06 MoM, and 1.14 MoM, respectively, consistent with a positive trisomy 21 risk of 1/269. Results of an amniocentesis revealed a small de novo interstitial duplication of 14q encompassing 14q31-q32.1. An array comparative genomic hybridization analysis detected a 6.6-Mb duplication at chromosome 14q31.3-q32.12. Results of a fluorescence in situ hybridization analysis showed a direct duplication of interstitial 14q. The karyotype was 46,XY,dup(14) (q31.3q32.12). Level II ultrasound was unremarkable. The parents decided to continue the pregnancy. A 3805-g healthy male baby was delivered at 39 weeks of gestation. When examined at 6 months of age, the neonate was normal in growth and psychomotor development with no apparent phenotypic abnormalities, although long-term follow-ups are required.ConclusionAbnormal maternal serum biochemistry in the second trimester may be a distinctive prenatal feature in pregnancy associated with fetal chromosome 14q duplication.     

Chromosome 4 deletions are frequent in invasive cervical cancer and differ between histologic variants

OBJECTIVE: Patterns of discontinuous deletion of chromosome 4 have been described in histologic variants of lung carcinomas and may represent different "hotspot" targets for gene-environment interactions. Since similar environmental risks exist for cervical cancer, we investigated patterns of discontinuous deletion in two major histologic variants. METHODS: Thirteen archival cases of squamous cell cancer (SCCA) and 11 cases of adenocarcinoma (AC) were precisely microdissected. Matched normal and tumor DNA were used for polymerase chain reaction (PCR) based loss of heterozygosity (LOH) analyses using 19 polymorphic markers spanning chromosome 4. Human papillomavirus (HPV) detection was determined by PCR using general and type-specific primers (HPV 16, 18). Differences in LOH between histologic tumor types and chromosomal regions were determined using Fisher's exact test. RESULTS: Loss at any chromosome 4 locus occurred in 92% of all tumors studied, with the majority of deletions occurring on the long arm of the chromosome. Four discrete minimal regions of discontinuous deletion (R) were identified. For these regions, LOH frequencies were 76% (R1, 4q34-q35), 48% (R2, 4q25-q26), 36% (R3, 4p15.1-p15.3), and 26% (R4, 4p16). Loss in SCCA predominated at 4q (4q34-q35; 83%) and in AC at 4p (4p15.3; 50%). Overall LOH on the p arm was significant in AC (82%) compared to SCCA (31%) (P = 0.02). HPV detection was similar in SCCA (85%) and AC (73%), and HPV 16/18 subtypes were similarly represented in both histologies. CONCLUSIONS: Chromosome 4 deletions are frequent in cervical carcinomas. Different patterns of deletion between SCCA and AC may represent gene regions targeted by different gene-environment interactions in these tumor subtypes.     

Terminal 14q deletion with unbalanced t(Y;14)(q12;q32) translocation

Terminal deletions of chromosome 14q are very rarely reported. Schneider et al. (2008) reviewed about 20 cases of 14q32 region deletion in a previous article and only three of the cases involved autosomal translocations; however, no sex chromosome translocations were reported. Here we report the clinical findings of a patient with terminal 14q32 deletion derivated from at (Y;14)(q12;q32) translocation.     

Molecular characterization of a ring chromosome 15 in a fetus with intra uterine growth retardation and diaphragmatic hernia

OBJECTIVE: To improve the phenotype-genotype correlation in terminal 15q deletions and ring chromosome 15 syndrome. METHODS: Echographic examination of fetus. R-banded chromosome and FISH analysis on cultured amniocytes. Microsatellite analysis to determine parental origin of the ring chromosome 15. Fetal autopsy. RESULTS: We report a new case of prenatal diagnosis of congenital diaphragmatic hernia and intrauterine growth retardation in a fetus with ring chromosome 15 involving 15q26.1-qter deletion. CONCLUSION: This case support the evidence that the region 15q26.3 is implicated in intrauterine growth retardation and suggests that the 15q critical region implicated in congenital diaphragmatic hernia is localized in 15q26.1-q26.2.     

Prenatal diagnosis and molecular cytogenetic characterization of a derivative chromosome der(18;18)(q10;q10)del(18)(q11.1q12.1)del(18)(q22.1q22.3) presenting as apparent isochromosome 18q in a fetus with holoprosencephaly

ObjectiveTo present prenatal diagnosis and molecular cytogenetic characterization of a derivative chromosome der(18;18)(q10;q10)del(18)(q11.1q12.1)del(18)(q22.1q22.3).Materials, Methods, and ResultsA 32-year-old woman was referred for genetic counseling of prenatally detected isochromosome 18q [i(18q)]. She had undergone amniocentesis at 19 gestational weeks because of a trisomy 18 risk of 1/39 derived from abnormally low levels of maternal serum unconjugated estriol, inhibin A, α-fetoprotein, and total β-human chorionic gonadotropin. Amniocentesis revealed a karyotype of 46,XX,i(18)(q10). Parental karyotypes were normal. Prenatal ultrasound showed alobar holoprosencephaly. Repeated amniocentesis was requested and performed at 21 gestational weeks. Array-comparative genomic hybridization analyses revealed a 14-Mb deletion of 18p11.32-p11.21, a 37.8-Mb duplication of 18q12.1-q22.1, and a 6.9-Mb duplication of 18q22.3-q23. Metaphase fluorescence in situ hybridization study showed the absence of an 18q12.1-specific probe signal in one arm and the absence of an 18q22.2-specific probe signal in the other arm of the derivative chromosome. Quantitative fluorescent polymerase chain reaction analysis determined a paternal origin of the derivative chromosome. The cytogenetic result was 46,XX,der(18;18)(q10;q10)del(18)(q11.1q12.1)del(18)(q22.1q22.3). The fetus postnatally manifested cebocephaly.ConclusionConcomitant monosomy 18p and trisomy 18q can be associated with holoprosencephaly and abnormal maternal serum screening results. Array-comparative genomic hybridization, fluorescence in situ hybridization, and quantitative fluorescent polymerase chain reaction are useful in genetic counseling of prenatally detected isochromosomes by providing information on the origin and genetic components of the isochromosome.     

Detection of fetal duplication 16p11.2q12.1 by next-generation sequencing of maternal plasma and invasive diagnosis

Objective: The objective of study is to report the feasibility of non-invasive prenatal screening (NIPS) combined with invasive detection by chromosomal analysis in identifying fetal duplication, providing clinical performance of NIPS on copy number variations (CNVs) detection.

Material and methods: NIPS was offered to a 35-year-old pregnant woman. Amniocentesis was performed to confirm the positive screening result. Fetal sample was detected by karyotyping, fluorescence in situ hybridization (FISH), and chromosomal microarray (CMA). Parental karyotyping was also conducted.

Results: NIPS result was positive for chromosome 16, indicating an extra copy of chromosome 16. FISH and chromosomal karyotyping revealed that the fetus had a marker chromosome derived from chromosome 16. CMA further demonstrated an approximately 19-Mb duplication in chromosome 16. The final fetal karyotype was 47,XY,+mar. ish der (16)(D16Z3+).arr 16p11.2q12.1 (30?624?186–49?696?337?×?3). Ultrasound scan and MRI showed some structure malformations.

Conclusions: A protocol for CNVs detection by combining a series of genetic methods was presented in this study and a novel marker duplication 16p11.2q12.1 was reported. With the ability to identify subchromosomal deletions and duplications in fetus, NIPS could reduce the possibility of invasive diagnosis. The followed confirmation test for positive sample is necessary and ensures the accuracy of the diagnosis.