一例软骨发育异常胎儿的遗传学分析

目的对1例软骨发育异常的胎儿进行遗传学分析,为产前诊断及评估其家庭的再发风险提供依据。方法对1例软骨发育异常的胎儿行G显带染色体核型分析、单核苷酸多态性微阵列(single nucleotide polymorphism-based arrays,SNP-Array)检测、荧光原位杂交(fluorescence in situ hybridization,FISH)及FGFR3基因突变检测。胎儿父母行外周血染色体核型分析、SNP-Array及FISH检测,以明确胎儿基因组变异的来源。结果胎儿脐血染色体核型为46,XY。脐血SNP-Array结果显示染色体Xp22.33区段存在3.7Mb微缺失,8q24.12区段存在538.4kb微重复,其缺失区段包含SHOX和ARSE等软骨发育相关基因;FGFR3基因未发生c.1138GA/C突变。根据胎儿及其父母SNP-array检测和FISH验证,胎儿携带的8q24.12微重复遗传自母亲,Xp22.33微缺失为新发突变。结论 Xp22.33微缺失是造成胎儿软骨发育异常的遗传学因素,因其为新发突变,在其家庭复发风险低。     

一例10q26.3微缺失合并18q22.3q23微重复患者的临床及遗传学分析

目的分析一例智力低下合并斜颈患者的遗传学病因。方法采集患者的外周血样, 常规进行G显带染色体核型分析以及单核苷酸多态性微阵列(single nucleotide polymorphism array, SNP-array)检测。结果患者染色体核型为46, XX;SNP-array检测显示其染色体10q26.3区存在3.8 Mb缺失, 涉及EBF3、ECHS1等21个OMIM基因, 同时染色体18q22.3q23区存在7.3 Mb重复, 涉及TSHZ1、TXNL4A等19个OMIM基因。根据美国医学遗传学与基因组学学会相关指南, 判断10q26.3缺失为致病性, 而18q22.3q23重复为临床意义不明。结论患者的临床表型应主要与10q26.3微缺失相关, 其中EBF3基因可能与智力发育障碍有关。上述结果为家系的遗传咨询提供了依据。     

1例罕见母源性11q及22q部分三体胎儿的产前诊断及遗传学分析

目的 对1例血清学筛查21三体高风险伴有侧脑室增宽的胎儿进行遗传学诊断。方法 联合应用常规G显带核型分析技术及CNV-seq测序技术对胎儿进行遗传学检测，并对双亲进行外周血染色体核型分析以明确胎儿染色体异常的来源。结果 胎儿染色体初步为47,XX,+mar。CNV-seq结果提示胎儿11q23.3-11q25存在18.25Mb重复，22q11.21-22q11.21存在1.35Mb重复。胎儿父亲染色体正常，母亲染色体为46,XX,t(11;22)(q23;q11.2)。胎儿核型结果最终确定为47,XX,+der(22)t(11;22)(q23;q11.2)。结论 胎儿携带有母源性11q部分三体和22q部分三体，可能导致严重的临床表型；明确胎儿的遗传学病因，指导家庭再次生育。     

产前诊断一例46，XX，del（4），dup（21）北大核心CSCD

目的探讨产前诊断的一例罕见染色体异常的遗传学机制及预后。方法对常规G显带核型分析发现的胎儿染色体可疑结构异常采用荧光原位杂交技术（fluorescence in situ hybridization,FISH）进行鉴定,同时应用全基因组基因芯片（whole genome DNA microarray）检测其染色体拷贝数变异。结果胎儿的一条21号染色体长臂疑似存在重复,即46,XX,dup（21）（？q21q22）,专一序列探针FISH检测证实21号杂交区域存在重复,即nucish21q22×3,基因芯片检测证实胎儿染色体21q21．3q22．3区存在17．87Mb的片段重复,涉及GATA1、JAK2、ALL等121个0MIM基因,涵盖唐氏综合征关键区,与颅面异常、心脏异常、智力低下、发育迟缓、四肢异常等相关。此外,胎儿还存在4p16．1p16．3区8．43Mb片段的缺失,涉及FGFR3、LETM1、WHSC1、WHSC2等64个OMIM基因,涵盖Wolf-Hirschhorn综合征疾病区域,与生长发育迟缓、头面部异常、心脏异常、智力低下、肌张力减退等相关。经咨询,其家属要求于孕25周时终止妊娠。结论当核型分析无法确定染色体的结构异常时,应该用特定位点的探针进行FISH检测有利于鉴别异常的类型,结合全基因组基因芯片检测,可以分析染色体拷贝数变异及其所涉及的致病基因,为临床预后及表型分析提供线索。     

21号环状染色体嵌合体胎儿2例的临床特征和遗传学分析

目的探讨2例21号环状染色体嵌合体胎儿的围产期临床表型和遗传学特征。方法选取2021年11月在厦门市妇幼保健院接受介入性产前诊断的2例胎儿为研究对象。收集2例胎儿的临床资料, 应用常规G显带核型分析和染色体微阵列分析(CMA)对2例胎儿及其父母进行遗传学检测。结果胎儿1超声提示胎儿鼻骨未显示、室间隔缺损、永存左上腔静脉、三尖瓣轻度返流, 染色体核型结果为46, X?, dic r(21;21)(p12q22;q22p12)[41]/45, X?, -21[9], CMA检测结果提示其染色体21q11.2q22.3区存在30.00 Mb片段的4拷贝, 21q22.3区存在3.00 Mb片段的缺失。胎儿2超声提示鼻骨呈点状回声, 核型为46, X?, r(21)(p12q22)[83]/45, X?, -21[14]/46, X?, dic r(21;21)(p12q22;q22p12)[3], CMA结果提示其染色体21q22.12q22.3区存在5.10 Mb片段的4拷贝, 21q22.3区存在2.30 Mb片段的缺失。结论 2例21号环状染色体嵌合体的围产期表型与靠近染色体缺失断裂位...     

母源性平衡易位t(6；14)所致胎儿不平衡易位1例的分析

目的探讨1例孕中期血清学筛查提示高风险胎儿的遗传学特征。方法该孕妇于2020年3月22日因"血清学筛查高风险"就诊于河南省人民医院。采用常规G显带染色体核型分析和微阵列比较基因组杂交(aCGH)对胎儿及孕妇夫妇进行检测。结果胎儿G显带染色体核型为46, XX, der(6)t(6;14)(q27;q31.2), 孕妇核型为46, XX, t(6;14)(q27;q31.2), 其丈夫核型未见异常。胎儿aCGH结果显示染色体6q26q27区存在6.64 Mb的缺失, 14q31.3q32.33区存在19.98 Mb重复, 均判断为致病性拷贝数变异。孕妇夫妇aCGH结果未见异常。结论胎儿的不平衡染色体异常可能缘于孕妇携带的平衡易位。aCGH有利于确定胎儿染色体异常的类型及断裂点, 为预测胎儿发生畸形的风险及后续妊娠的选择提供依据。     

无创产前检测染色体拷贝数变异阳性病例的诊断与分析

目的探讨利用羊水细胞染色体核型分析和单核苷酸多态芯片(single-nucleotide polymorphism arrays,SNP-Array)验证无创产前检测(noninvasive prenatal test,NIPT)胎儿基因组拷贝数变异(genome-wide copy number variation,CNVs)阳性结果的临床意义。方法对NIPT筛查拷贝数变异(CNVs)阳性的病例进行产前超声检查、遗传咨询并进行介入性产前诊断,送检染色体核型分析及SNP-Array基因芯片检测验证NIPT的结果,随访妊娠结局。结果 2015年6月~2017年10月期间送检的NIPT检查,其中3例CNVs筛查阳性病例完成验证检查。病例1 NIPT提示20号染色体23Mb重复的一例,经验证为20p13处1.3Mb的缺失;病例2 NIPT提示11号染色体缺失9.5Mb,经验证为11号染色体q24.2-q25缺失8.5Mb;病例3 NIPT提示13号染色体重复2.58Mb,经验证为13号染色体q12.11-q12.12重复2.8Mb,并发现了4号染色体杂合性缺失21.3Mb。结论 NIPT筛查拷贝数变异阳性结果需要验证,经典的羊水细胞染色体核型分析技术可以验证胎儿染色体数目和结构异常,SNP-Array芯片则分辨率更高。     

染色体微阵列产前诊断8q13.3微缺失一例

目的应用染色体微阵列分析(chromosome microarray analysis,CMA)技术对1例超声结构异常胎儿进行全基因组拷贝数变异(copy number variations,CNVs)检测,探讨CMA在超声结构异常胎儿产前诊断中的意义。方法应用常规G显带染色体核型分析胎儿及其父母的染色体核型,应用CMA技术分析胎儿及其父母的CNVs。结果G显带核型分析显示胎儿核型与母亲一致,为46,XN,t(8;11)(q21.2;q13)mat,父亲核型正常;父母CMA检测结果均未见异常;胎儿的检测结果为arr[GRCh37]8q13.3(71314082-73322915)×1,提示一条8号染色体的8q13.3区域发生2.00 Mb缺失。结论超声结构异常胎儿染色体核型分析检出的平衡易位,需借助CMA等技术进一步确定是否存在微缺失微重复。     

应用微阵列比较基因组杂交技术对胎儿复杂染色体易位的产前诊断

目的对产前羊水细胞培养染色体核型分析,检测出染色体易位的胎儿应查父母双方染色体,并用基于芯片的微阵列比较基因组杂交(array comparative genomic hybridization,a CGH)技术检测,以明确其易位染色体的来源及胎儿染色体有无微重复或微缺失,探讨微阵列比较基因组杂交(a CGH)技术在检测胎儿染色体异常中的临床价值。方法通过胎儿羊水细胞培养,染色体G显带核型分析,诊断出胎儿染色体异常,核型为46,X,t(X;13;9)(q13;q14;p22),t(3;6)(p13;q23)。对此例标本进行a CGH分析,通过多位点高分辨率扫描确定胎儿染色体有无微重复或微缺失。结果a CGH扫描检测出胎儿染色体在Xq13.1-q13.2(71,699,190-71,820,393)区带存在121kb的缺失,在13q14.2-q21.1(48,706,590-57,520,639)区带存在8.8Mb的缺失。结论利用a CGH技术可以方便快速地鉴定和分析染色体的微重复或微缺失,结合传统的核型分析技术,可以为判断重复或缺失染色体片段的遗传学效应和产前诊断提供帮助。     

一例全前脑畸形胎儿的临床及遗传学分析

目的明确一全前脑畸形胎儿的致病原因,为该家系的遗传咨询提供依据。方法收集胎儿的孕期超声资料,应用全外显子测序技术(whole exon sequencing,WES)检测患儿的致病原因,低深度高通量测序技术对胎儿及其父母进行染色体拷贝数变异(copy number variant,CNV)检测,染色体细胞培养方法分析夫妻双方核型。结果胎儿孕期超声提示胎儿脑部结构异常,经诊断后明确为全前脑畸形。WES结果提示胎儿13号染色体存在约33 Mb片段缺失,缺失区域包含1个单倍剂量敏感基因ZIC2。染色体CNV检测结果提示胎儿13号染色体13q31.1-34区域存在32.32 Mb缺失,而夫妻双方均未发现相同的染色体片段缺失。夫妻双方核型分析结果未发现染色体大的结构改变。结论根据临床资料胎儿确诊为全前脑畸形,遗传学检测明确其致病原因为包含单倍剂量敏感基因ZIC2的13号染色体片段缺失。     

A translocation between Xq21.33 and 22q13.33 causes an intragenic SHANK3 deletion in a woman with Phelan-McDermid syndrome and hypergonadotropic hypogonadism

Chromosome 22q13 monosomy has been described as a contiguous gene syndrome. Localized in the critical region, SHANK3 is likely to play a key role in the expression of the clinical phenotype. SHANK3 mutations have also been reported in autistic patients without a syndromic phenotype. We report on a 20-year-old woman with mental retardation carrying a de novo translocation between chromosome Xq21.33 and 22q13.33, associated with a duplication on Xq21.33 and deletion on 22q13.33. As a child her development was characterized by disturbed social interaction, stereotypic hand movements and ritualistic behavior and she was considered at one time to have autistic features. All these traits match the 22q13 deletion syndrome (Phelan-McDermid syndrome, OMIM 606232), likely due to the deletion overlapping the last two exons of the SHANK3 gene. Our patient harbors the smallest and most distal SHANK3 deletion described to date, yet resulting in the full spectrum of the Phelan-McDermid syndrome. In addition, she has hypergonadotropic hypogonadism with low estrogen level, high FSH level, and irregular menstruation. Intriguingly, chromosome translocations affecting the chromosome band Xq21 can result in premature ovarian failure.     

一例22号环状染色体合并22ql3微缺失综合征患儿的临床及遗传学分析

目的探讨1例语言发育滞后患儿的遗传学病因。方法对患儿进行外周血染色体G显带分析以及单核昔酸多态性微阵列芯片(single nucleotide polymorphism microarray,SNP array)检测。结果患儿染色体核型为46,XY,r(22)(pll.2ql3),SNP array检测在22ql3区发现一处1.67 Mb的缺失,具体为arr[Hgl9]22ql3.33(49531302〜51197766)X1O结论患儿同时携带22号环状染色体以及22ql3微缺失,为明确其病因和遗传咨询提供了重要的线索。     

Genetic and metabolic profiling of individuals with Phelan-McDermid syndrome presenting with seizures

Phelan-McDermid syndrome (PMS) (OMIM*606232) is a rare genetic disorder characterized by intellectual disability, autistic features, speech delay, minor dysmorphia, and seizures. This study was conducted to investigate the prevalence of seizures and the association with genetic and metabolic features since there has been little research related to seizures in PMS. For 57 individuals, seizure data was collected from caregiver interviews, genetic data from existing cytogenetic records and Sanger sequencing for nine 22q13 genes, and metabolic profiling from the Phenotype Mammalian MicroArray (PM-M) developed by Biolog. Results showed that 46% of individuals had seizures with the most common type being absence and grand-mal seizures. Seizures were most prevalent in individuals with pathogenic SHANK3 mutations (70%), those with deletion sizes >4 Mb (16%), and those with deletion sizes <4 Mb (71%) suggesting involvement of genes in addition to SHANK3. Additionally, a 3 Mb genomic region on 22q13.31 containing the gene TBC1D22A, was found to be significantly associated with seizure prevalence. A distinct metabolic profile was identified for individuals with PMS with seizures and suggested among other features a disrupted utilization of main energy sources using Biolog plates. The results of this study will be helpful for clinicians and families in anticipating seizures in these children and for researchers to identify candidate genes for the seizure phenotype.     

Clinical and molecular cytogenetic analysis of a family with mental retardation caused by an unbalanced translocation involving chromosomes 3 and 22北大核心CSCD

Objective To explore the genetic cause of a Chinese boy with unexplained mental retardation, and analyzethe pattern of inheritance for his family. Methods Routine karyotyping, chromosomal microarray analysis (CMA),and fluorescence in situ hybridization (FISH) were used to detect chromosome abnormalities in the patient andhis families. Results Chromosome analysis suggested that the proband and 7 affected individuals had anidentical karyotype 46,XN,der(22)t(3;22)(q28;ql3)pat, while his father and 5 other relatives carried a samekaryotype of 46, XN, t(3;22) (q28;ql3). His mother and other family members were normal. CMA analysis confirmed that the patient had a 9. 0 Mb duplication at 3q28q29, in addition with a 1. 7 Mb deletion at 22ql3. 3. Aboveresults were confirmed by FISH. Conclusion The abnormal phenotypes of the proband and his family members fromfive generations have conformed to those of 3q duplication and 22ql3. 3 deletion caused by unbalancedtranslocation involving chromosomes 3q and 22q. The presence of multiple patients in this family may beattributed to abnormal gametes produced by parental balanced translocations involving 3q and 22q.     

Molecular characterisation of patients with subtelomeric 22q abnormalities using chromosome specific array-based comparative genomic hybridisation

The 22q13 deletion syndrome is associated with global developmental delay, absent or delayed speech, and generalised hypotonia. In this study, the size and nature of 22q13 deletions (n=9) were studied in detail by high-resolution chromosome specific array-based comparative genomic hybridisation (array CGH). The deletion sizes varied considerably between the different patients, that is, the largest deletion spanning 8.4 Mb with the breakpoint mapping to 22q13.2 and the smallest deletion spanning 3.3 Mb with the breakpoint mapping to 22q13.31. In one case, a unique subtelomeric 3.9 Mb deletion associated with a 2.0 Mb duplication of 22q13 was observed, adding to a growing number of similar cases identified for other chromosome ends. Remarkably, this patient had signs suggestive of retinitis pigmentosa, which has never been reported before in the 22q13 deletion syndrome. The identification of two pairs of recurrent proximal breakpoints on 22q13 suggests that these specific regions may be prone to recombination, due to yet unknown genome architectural features. In addition to the copy number changes on 22q13, a duplication of approximately 330 kb on 22q11.1 was observed and shown to be a genetic large-scale copy number variation without clinical consequences. The current study failed to reveal relationships between the clinical features and the deletion sizes. Global developmental delay and absent or severely delayed speech were observed in all patients, whereas hypotonia was present in 89% of the cases (8/9). This study underscores the utility of array CGH for characterising the size and nature of subtelomeric deletions, such as monosomy 22q13, and underlines the considerable variability in deletion size in the 22q13 deletion syndrome regardless of the clinical phenotype.     

Further evidence of GABRA4 and TOP3B as autism susceptibility genes

Chromosomal copy number variants (CNVs) are known contributors to neurodevelopmental conditions such as autism spectrum disorder (ASD). Both array comparative genomic hybridization and next-generation sequencing techniques have led to an increased detection of small CNVs and the identification of many candidate susceptibility genes for ASD. We report familial inheritance of two CNVs that include genes with known involvement in neurodevelopment. These CNVs are found in various combinations among four siblings with autism spectrum disorder, as well as in their neurodevelopmentally normal parents. We describe a 2.4 Mb duplication of 4p12 to 4p11 that includes GABRA4 (OMIM: 137141) and other GABA receptor genes, as well as a 246 kb deletion at 22q11.22 involving the TOP3B gene (OMIM: 603582). The maternally inherited 4p duplication was detected in three siblings, two of whom also had the paternally inherited 22q11.22 deletion. The fourth sibling only had the 22q11.22 deletion. These CNVs have rarely been reported in the literature. Upon review, a single publication was found describing a similar 4p duplication in three generations of a family with neurodevelopmental and neuropsychiatric disorders, as well as in an unrelated patient with autism (Polan et al., 2014). TOP3B falls within the distal 22q11.22 microdeletion syndrome and has been associated with schizophrenia, neurodevelopmental disorders including epilepsy, and cardiac defects. The identification of this family contributes to the understanding of specific genetic contributors to neurodevelopmental disorders and an emerging phenotype associated with proximal 4p duplication.     

两例合并3q微缺失的先天性心脏病胎儿的遗传学分析CSCD

目的明确2例先天性心脏病（congenital heart disease,CHD）胎儿的基因组拷贝数变异（copy number variations,CNVs）的性质,探讨3q微缺失与cHD的关系。方法提取CHD胎儿脐带组织的DNA,用全基因组低覆盖度测序检测其CNVs。结果2例CHD胎儿均携带3q微缺失。病例1表现为室间隔缺损、唇腭裂,携带3q29区1．66Mb的缺失,涉及3q29微缺失综合征的所有关键基因。病例2表现为主动脉骑跨、室间隔缺损,携带3q28区240kb的缺失,未发现明确与该片段相关的致病信息。结论3q29微缺失可能导致CHD、唇腭裂等多发畸形。全基因组低覆盖度测序可用于检测CNVs。     

Consensus recommendations on counselling in Phelan-McDermid syndrome,with special attention to recurrence risk and to ring chromosome 22

This paper focuses on genetic counselling in Phelan-McDermid syndrome (PMS), a rare neurodevelopmental disorder caused by a deletion 22q13.3 or a pathogenic variant in SHANK3. It is one of a series of papers written by the European PMS consortium as a consensus guideline. We reviewed the available literature based on pre-set questions to formulate recommendations on counselling, diagnostic work-up and surveillance for tumours related to ring chromosome 22. All recommendations were approved by the consortium, which consists of professionals and patient representatives, using a voting procedure. PMS can only rarely be diagnosed based solely on clinical features and requires confirmation via genetic testing. In most cases, the family will be referred to a clinical geneticist for counselling after the genetic diagnosis has been made. Family members will be investigated and, if indicated, the chance of recurrence discussed with them. Most individuals with PMS have a de novo deletion or a pathogenic variant of SHANK3. The 22q13.3 deletion can be a simple deletion, a ring chromosome 22, or the result of a parental balanced chromosomal anomaly, influencing the risk of recurrence. Individuals with a ring chromosome 22 have an increased risk of NF2-related schwannomatosis (formerly neurofibromatosis type 2) and atypical teratoid rhabdoid tumours, which are associated with the tumour-suppressor genes NF2 and SMARCB1, respectively, and both genes are located on chromosome 22. The prevalence of PMS due to a ring chromosome 22 is estimated to be 10–20%. The risk of developing a tumour in an individual with a ring chromosome 22 can be calculated as 2–4%. However, those individuals who do develop tumours often have multiple. We recommend referring all individuals with PMS and their parents to a clinical geneticist or a comparably experienced medical specialist for genetic counselling, further genetic testing, follow-up and discussion of prenatal diagnostic testing in subsequent pregnancies. We also recommend karyotyping to diagnose or exclude a ring chromosome 22 in individuals with a deletion 22q13.3 detected by molecular tests. If a ring chromosome 22 is found, we recommend discussing personalised follow-up for NF2-related tumours and specifically cerebral imaging between the age of 14 and 16 years.     

A de novo 7.9 Mb deletion in 22q13.2→qter in a boy with autistic features,epilepsy, developmental delay,atopic dermatitis and abnormal immunological findings

We report a 5-year-old boy with mental retardation, autistic features, epilepsy, developmental delay, atopic dermatitis and abnormal immunological findings, carrying a 7.9 Mb de novo deletion of chromosome 22q13.2→qter. This region contains the SHANK3, NCAPH2 and CYP2D6 genes which are associated with T-cell immune response. The present case provides evidence that 22q13 deletion syndrome may be associated with immune system dysfunction in addition to neuropsychiatric disorders.