小儿先天异常的细胞遗传学分析

目的 对临床怀疑染色体病或需排除染色体畸变的患儿进行细胞遗传学染色体检查，以探讨小儿先天异常与染色体异常之间的关系。方法 对小儿先天异常就诊者取外周血，37℃培养，常规制片，G显带，行染色体分析。结果 共检查299例小儿先天异常患者的染色体，其中因智力低下就诊者225例。共发现异常核型129例，占43．14％，其中常染色体数目异常102例，嵌合体4例，常染色体结构异常10例，性染色体数目异常4例，染色体与社会性别不符7例。结论 染色体畸变是小儿先天异常特别是小儿智力低下的主要原因之一。     

胎儿染色体检查在复发性流产患者中的应用价值

胎儿染色体非整倍体是引起自发性流产最主要的原因,但对于大部分复发性（Recurrent Pregnancy Loss,RPL）流产夫妇而言,其胎儿染色体异常的几率降低,因此,复发性流产的流产物染色体核型分析用于日常的检测价值受到了质疑。本文回顾了胎儿染色体异常在RPL 人群中的发生率,在 RPL 的诊疗过程中,流产物遗传学检测的进展、流产物基因检测的临床价值,以及 RPL 人群是否是植入前遗传学筛查的适应人群。     

A survey of undetected,clinically relevant chromosome abnormalities when replacing postnatal karyotyping by Whole Genome Sequencing

Whole genome sequencing (WGS) holds the potential to identify pathogenic gene mutations, copy number variation, uniparental disomy and structural rearrangements in a single genetic test. With its high diagnostic yield and decreasing costs, the question arises whether WGS can serve as a single test for all referrals to diagnostic genome laboratories (“one test fits all”). Here, we provide an estimate for the proportion of clinically relevant aberrations identified by light microscopy in postnatal referrals that would go undetected by WGS. To this end, we compiled the clinically relevant abnormal findings for each of the different referral categories in our laboratory during the period 2006–2015. We assumed that WGS would be performed on 300–500 bp DNA fragments with 150-bp paired sequence reads, and that the mean genome coverage is 30x, corresponding to current practice. For the detection of chromosomal mosaicism we set minimum thresholds of 10% for monosomy and 20% for trisomy. Based on the literature we assumed that balanced Robertsonian translocations and ∼9% of other, balanced chromosome rearrangements would not be detectable because of breakpoints in sequences of repetitive DNA. Based on our analysis of all 14,957 referrals, including 1455 abnormal cases, we show that at least 8.1% of these abnormalities would escape detection (corresponding to 0.79% of all referrals). The highest rate occurs in referrals of premature ovarian failure, as 73.3% of abnormalities would not be identified because of the frequent occurrence of low-level sex chromosome mosaicism. Among referrals of recurrent miscarriage, 25.6% of abnormalities would go undetected, mainly because of a high proportion of balanced Robertsonian translocations. In referrals of mental retardation (with or without multiple congenital anomalies) the abnormality would be missed in only 0.35% of referrals. These include cases without imbalances of unique DNA sequences but of clinical relevance, as for example, r(20) epilepsy syndrome. The expected shift to large-scale implementation of WGS (“one test fits most”) as initial genetic test will be beneficial to patients and their families, since a cause for the clinical phenotype can be identified in more cases by a single genetic test at an early phase in the diagnostic process. However, a niche for genome analysis by light microscopy will remain. For example, in referrals of newborns with a suspicion of Down syndrome, karyotyping is not only a cost-effective method for providing a quick diagnosis, but also discriminates between trisomy 21 and a Robertsonian translocation involving chromosome 21. Thus, when replacing karyotyping by WGS, one must be aware of the rates and spectra of undetected abnormalities. In addition, it is equally important that requirements for cytogenetic follow-up studies are recognized.     

单核苷酸多态性芯片与染色体核型分析在唐氏筛查高风险孕妇产前诊断中的比较研究

目的:探讨单核苷酸多态性芯片(SNP array)在唐氏筛查高风险孕妇胎儿染色体分析中的应用价值。方法:选取312例因唐氏筛查高风险的孕妇,行羊膜腔穿刺术后获得羊水,对羊水进行G显带核型分析和SNP array检测,比较核型分析与SNP array检测结果,并按年龄分组比较拷贝数变异(CNVs)的发生率差别。结果:核型分析和SNP array均准确发现2例21三体(0.64%),6例核型分析提示染色体平衡重组(1.92%)的样本经SNP array分析证实不存在重排片段重复或缺失。在303例核型正常的胎儿羊水细胞中,SNP array检测发现176例CNVs,其中良性CNVs 106例,临床意义不明确的CNVs(VOUS)61例,新发CNVs(de novo CNVs)9例,未发现已知的致病性CNVs。唐氏筛查高风险组与唐氏筛查高风险合并高龄组CNVs的分布差别无统计学意义(P0.05)。此外,本研究中首次报道14种CNVs。结论:SNP array可进一步确定核型分析的平衡易位是否存在染色体微缺失/重复。在核型正常的胎儿中,SNP array可检测出大量拷贝数异常,发现14种新的CNVs但现有数据库无法判断其临床意义,需进一步研究确认。此外,孕妇年龄对胎儿基因组中新发CNVs的发生率无明显影响。     

骨髓增生异常综合征T淋巴细胞异常与克隆造血

 目的　了解T淋巴细胞异常在骨髓增生异常综合征（MDS）克隆造血中的作用。方法　对76例MDS患者的染色体核型、T淋巴细胞亚群及激活状态进行分析。结果　正常核型36例,异常核型40例,异常发生率52.6 %。40例异常核型中,三体8（+8）24例,占异常核型的60.0 %。与健康对照组比较,MDS患者CD+3 CD-19、CD+3 CD-4 CD+8以及CD+3 HLA-DR+细胞百分率显著升高,CD-3（CD16 CD56）+细胞的百分率明显降低。将MDS患者进行核型分组,异常核型组CD+3（CD16 CD56）+细胞的百分率显著高于正常对照组。将+8核型从MDS异常核型中独立出来进行分析,CD+3 CD+4 CD-8细胞的百分率明显低于正常核型以及其他异常组,CD4／CD8的比值明显低于健康对照组。结论　MDS存在T淋巴细胞异常,异常核型MDS可能恶性克隆增殖更为优势,预后更差。+8 核型MDS存在更为严重的免疫监视功能下降,导致恶性克隆过度增殖与残存造血过度受抑。     

Ewing sarcoma/primitive neuroectodermal tumor of the kidney: a case report. Diagnosed by immunohistochemistry and molecular analysis

BACKGROUND: Ewing sarcoma/primitive neuroectodermal tumor (EWS/PNET) of the kidney is a rare and aggressive tumor. It has a rapid clinical progression with early metastasis and death. Few cases with documented t(11;22) have been reported in the literature. CASE PRESENTATION: We report a case of EWS/PNET of the kidney in a 26-year-old woman with widespread metastasis at initial presentation. The tumor cells showed strong expression for CD99 and FLI-1 monoclonal antibodies and polyclonal antibodies and were negative for WT1 and numerous other markers. The diagnosis was subsequently confirmed by demonstrating t(11;22)(q24;q12) using cytogenetic karyotyping and fluorescence in situ hybridization. CONCLUSIONS: Due to the different prognosis and management between EWS/PNET and other primary renal neoplasms with similar morphology, a histopathologic diagnosis with extreme accuracy should be made. Cytogenetic analysis is an important supportive tool to immunohistochemistry in making the final diagnosis.     

异常核型骨髓增生异常综合征64例预后分析

 【摘要】　目的　探讨骨髓增生异常综合征（MDS）患者染色体异常与预后的关系,对治疗效果进行分析。方法　回顾性分析122例MDS患者染色体核型,用吉姆萨显带法进行检测。难治性贫血（RA）、环形铁幼粒细胞难治性贫血（RAS）的治疗以诱导分化剂及刺激造血药物为主。原始细胞过多难治性贫血（RAEB）、转化型原始细胞过多难治性贫血（RAEB-t）、慢性粒-单核细胞白血病（CMML）的治疗以小剂量化疗和小剂量联合化疗方案为主。分析异常核型MDS患者疗效,以同期住院的正常核型MDS患者为对照。结果　检出异常核型MDS患者64例,治疗后完全缓解（CR）17例,CR率26.6 %。同期正常核型MDS患者58例,CR 30例,CR率51.7 %。正常和异常核型患者CR率差异有统计学意义（χ2＝8.13,P＝0.04）。复杂核型、-7、+8核型异常者易进展为急性白血病。结论　染色体核型分析在MDS的诊断与预后判断中有重要意义,不同的染色体核型改变进展为白血病的风险不同。     

荧光原位杂交检测急性髓性白血病21号染色体复杂核型异常

目的对急性髓性白血病（AML）患者可能出现的21号染色体复杂核型异常进行研究。方法AML患者共50例,其中成人37例,儿童13例,采用荧光原位杂交技术（FISH）,运用多种位点特异性DNA探针（染色体全染、特殊位点、双色易位融合探针）进行杂交。结果50例AML中,7例患者出现21号染色体异常（14％）,包括21号染色体数量和结构上的异常。其中4例儿童AML出现21号染色体三倍体,1例合并复杂的核型变化：47～49,XX,der（1）t（1;17）（p36．1;q23）,＋4,＋10,der（11）t（11;17）（q23;q23）,-17,-18,＋20,＋21。3例成人AML出现21号染色体结构的变化,即t（8;21）（q22;q22）。其中1例患者出现复杂的核型变化,即der（21）,t（8;21）（q22;q22）,dup（15q）。结论AML常合并有21号染色体畸变。儿童及成人AML出现21号染色体畸变的方式不同：前者多见21号染色体数量上的变化,而后者多见21号染色体结构上的变化。     

清远地区976例细胞遗传学实验诊断与临床分析

目的：通过对清远地区976例细胞遗传及临床资料分析，以了解该地区染色体病在临床常见疾病中的发生率、相关性及异常核型。方法：常规外周血淋巴细胞及羊水细胞培养，收获制片、胰酶消化G显带核型分析。结果：发现异常核型79例，其中常染色体数目和结构异常47例，性染色体异常27例，异常率分别为59．49％及40．51％；异常核型涉及到3、9、13、14、16、18、20、21、22、X、Y共11条染色体共计26种核型。结论：两性畸形、先天愚型、男性不育症染色体病风险率高；染色体异常是导致闭经、不孕、流产及病理妊娠不可忽略的重要因素。