TBX1基因与染色体22q11.2微缺失综合征

染色体22q11·2微缺失综合征(22q11·2DS)是人类最常见的染色体微缺失综合征。TBX1基因作为一个T-BOX家族转录因子,其单拷贝缺失可能是22q11·2DS的主要原因之一,它对该综合征临床表征的出现可能有重要作用。TBX1在胚胎生长发育是胚胎咽部分节、咽弓和动脉弓形成、心脏流出道生长与排列及分隔等过程所必需的基因。TBX1受一系列调控基因调节,其本身也调控一系列基因。     

应用PCR技术检测先心病患者中22q11微缺失

目的为了建立一种在先天性心脏病（congenital heart disease,CHD）患者中快速、有效检测染色体22q11微缺失检测方法。方法从22q11区域内选取5个短串联重复多态位点（STRs）（D22S941、D22S944、D22S264、D22S311、D22S306）,应用PCR扩增方法对20例CHD患者及其父母进行22q11微缺失筛查。结果发现4例CHD患者可能存在22q11微缺失。对筛查出可疑阳性病例再运用荧光标记PCR—STR分型方法进行诊断,结果有1例确诊为D22s941缺失。结论此项研究表明普通PCR方法只能作为22q11微缺失筛查的一种手段,荧光标记PCR—STR分型由于准确、高效,可以作为22qll微缺失确诊方法。     

先天性心脏病患儿22q11微缺失的定量荧光聚合酶链反应检测

目的 建立对22q11染色体微缺失进行快速批量检测的技术,用于非综合征先天性心脏病患 者染色体微缺失情况的检测.方法 采用定量荧光聚合酶链反应(quantitative fluorescent polymerase chain reaction,QF-PCR)法和8个短串联重复(short tandem repeat,STR)多态标记对79例中国汉族非综合征先天性心脏病(congenital heart defects,CHD)患者和84名正常对照者进行染色体22q11微缺失的检测.结果 缺失区域的STR标记在受检的非综合征型先天性心脏病患者中的平均杂合率为0.76,在正常对照人群中为0.79.在受检的1例法洛氏四联症患儿中检测到22q11微缺失(1.3%),经多重连接依赖探针扩增(multiplex ligation-dependent probe amplification,MLPA)技术验证结果正确.结论 采用QF-PCR法,可以高效批量地对22q11染色体微缺失进行筛查.     

多重连接依赖的探针扩增技术在检测先天性心脏病遗传学病因中的应用

目的探讨多重连接依赖的探针扩增技术(MLPA)用于检测先天性心脏病遗传学病因的可行性。方法 2010年11月至2015年12月间,共收集110例散发的先天性心脏畸形患儿样本进行MLPA检测,将不同试剂盒Kit P311-A2和Kit P250-B1获得的扩增产物信息经Coffalyser DB v140701软件(Holland-MRC公司)进行定量分析,观察样本DNA拷贝数的变化,并将所得结果进行比较。结果 110例先天性心脏畸形患儿中,本实验所用的MLPA-P250试剂盒共检出5例22q11.2微缺失,1例22q11A-C区微重复,阳性检出率5.5%(6/110);MLPA-P311试剂盒共检出3例22q11.2微缺失,其他基因杂合缺失3例,22q11.2微重复1例,阳性检出率6.4%(7/110),两个试剂盒在检测22q11.2微缺失/微重复方面的结果吻合,可相互补充检测先天性心脏病病因。结论 MLPA可作为高效、简便的方法检测先天性心脏病患儿基因拷贝数的变异,具有较好的临床应用价值。     

先天性心脏病患者22q11微缺失检测及相关分析

目的探讨5个短串联重复（short tandem repeat，STR）标记用于检测22q11微缺失的可行性，了解中国汉族未经挑选的先天性心脏畸形患者中22q11微缺失的发生情况。方法选择位于22q11缺失区域的5个STR标记，对163例中国汉族先天性心脏畸形（congenital heart defect，CHD）息者及双亲进行单倍型分析，对检出的阳性病例及部分阴性病例进行荧光原位杂交（fluorescence in situ hybridization，FISH）验证。结果5个标记均具有较好的信息量，22D_4_1和22D_4_2杂合率分别为0．65和0．52，22D_4_3、22D_4_4和D22S873杂合率均在0．7以上，可用于汉族人群多态性分析；163例先天性心脏畸形患者用STR标记检出12例22q11微缺失，其中9例得到FISH检测证实，2例微小缺失和1例远端缺失FISH检测为阴性；CHD患者22q11微缺失检出率为7．36％，室间隔缺损微缺失检出率为8．18％（9／110），法乐氏四联征检出率为14．3％（3／21），其它类型的CHD未检出缺失。结论5个STR标记可用于汉族人群22q11微缺失的检测，且有快速、成本低的优点；中国汉族CHD患者中存在一定比率的22q11微缺失，尤其是室间隔缺损和法乐氏四联征较为常见。     

荧光原位杂交在产前诊断胎儿先心病22q11微缺失中的应用

目的应用荧光原位杂交（FISH）技术检测胎儿染色体22q11微缺失,以探讨该技术在胎儿先天性心脏病病因检测中的临床应用。方法对41例产前诊断有各类心脏畸形、且染色体核型分析结果未见明显异常的胎儿以及1例先证者进行FISH检测,检测探针位于22q11微缺失综合征微缺失关键区域22q11的TUPLE1基因,与22q末端ARSA基因。结果 41例胎儿FISH检测均成功,所有胎儿22q11两位点均未发现微缺失;一胎儿家庭的1名先证者经检测确证为22q11微缺失综合征患者。结论胎儿心脏畸形有多种病因,常规染色体检查仅能检出其中一部分染色体数目异常,对于各种微缺失综合征,仍然需要FISH、芯片等更高分辨率的技术手段应用,对相关可能的致病位点进行针对性检测或筛检,以提高病因检出率,防止心脏畸形患儿出生。     

微阵列基因组杂交技术在22q11．21微缺失家系中的应用研究

目的了解反复孕育严重先天性心脏病儿、胎儿父亲患有原发性甲状旁腺功能低下家系的基因组拷贝数变化,确定其发病的遗传学原因。方法对常规染色体核型分析未见异常的法洛氏四联症胎儿及其整个家系中的7人采用微阵列基因组杂交（array—based comparative genomic hybridization,array—CGH）技术进行基因组拷贝数变化的检测分析（copy number variations,CNVs）。结果经过array—CGH分析,在胎儿及其父亲的22q11．21均发现存在2．52Mb的致病性缺失片段,位于18,919,942—21,440,514区段。家系中其他成员未发现同样的片段异常。结论22q11．21微缺失是导致其父亲患原发性甲状旁腺功能减退的遗传学原因,也是该家系多次孕育严重先天性心脏病患儿的原因,同时表明22q11．21微缺失表型多样,临床症状差异大。array—CGH是一种高通量、高分辨率及高准确性的遗传学分析技术,能够发现染色体片段上的亚微结构异常,是临床遗传学研究的重要工具。     

22q11．2微缺失综合征研究现况

22q11．2微缺失综合征是染色体22q11．21-q11．23缺失引起的遗传综合征，典型缺失区域内低重复序列(LCR22s)间的重组可能介导了缺失的发生。此综合征可表现为心脏、颅面、免疫等系统异常，已有研究对Tbx1、Ufd1L等相关基因进行探讨，现就其发病机制、临床特征、诊断与产前诊断作一综述。     

TBX1基因的研究进展

T-box家族是近年来引起国内外学者高度重视的一个转录因子家族，它们在心脏发育和遗传性疾病的发生中发挥着重要作用。TBX1转录因子在早期心脏发育，尤其是在心脏流出道的发生中起着重要作用。TBX1基因与人类22q11．2微缺失综合征的相关性是近年研究的热点问题。本文从结构特征、在胚胎发育过程中的表达、相关疾病及与其他基因的关系几方面对TBX1近几年的研究进展作一综述。     

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。     

An association study between the genetic polymorphisms within TBX1 and schizophrenia in the Chinese population

The strong association between common psychiatric disorders and the 22q11.2 microdeletion suggests that haploinsufficiency of one or more genes in the region confers susceptibility to these disorders. Recent mouse studies have shown that the T-box 1 (TBX1) gene in the 22q11.2 region can cause prepulse inhibition (PPI) impairment in the heterozygous state. A study has also shown that phenotypic features of 22q11 deletion syndrome (22q11DS) were segregated with an inactivating mutation of TBX1 in one family, suggesting that the TBX1 gene plays a role in the pathogenesis of some psychiatric disorders. We performed an association study between three single nucleotide polymorphisms (SNPs) in the TBX1 gene and schizophrenia. However, we found no significant difference in the genotype or allele distributions between the 328 schizophrenics and 288 controls for any of the polymorphisms, nor was there any haplotype association. Our data suggest that the genetic polymorphisms within TBX1 do not confer an increased susceptibility to schizophrenia in the Chinese population.     

Atypical deletion of 22q11.2: Detection using the FISH TBX1 probe and molecular characterization with high-density SNP arrays

Despite the heterogeneous clinical presentations, the majority of patients with 22q11.2 deletion syndrome (22q11.2 DS) have either a common recurrent 3 Mb deletion or a less common, 1.5 Mb nested deletion, with breakpoint sites in flanking low-copy repeats (LCR) sequences. Only a small number of atypical deletions have been reported and precisely defined. Haploinsufficiency of the TBX1 gene was determined to be the likely cause of 22q11.2 DS. The diagnostic procedure usually used is FISH using commercially probes (N25 or TUPLE1). However, this test does not contain TBX1, and fails to detect deletions that are either proximal or distal to the FISH probes. Here, we report on two patients with clinical features suggestive of 22q11.2 DS, a male infant with facial dysmorphia, pulmonary atresia, ventricular septal defect, neonatal hypocalcemia, and his affected mother, with facial dysmorphia, learning disabilities, and hypernasal speech. They were tested negative for 22q11.2 DS using N25 or TUPLE1 probes, but were shown deleted for a probe containing TBX1. Delineation of the deletion was performed using high-density SNP arrays (Illumina, 370K). This atypical deletion was spanning 1.89 Mb. The distal breakpoint resided in LCR-D, sharing the same distal breakpoint with the 3 Mb common deletion. The proximal breakpoint was located 105 kb telomeric to TUPLE1, representing a new breakpoint variant that does not correspond to known LCRs of 22q11.2. We conclude that FISH with the TBX1 probe is an accurate diagnostic tool for 22q11.2 DS, with a higher sensitivity than FISH using standard probes, detecting all but the rarest deletions, greatly reducing the false negative rate.     

评价多重连接探针扩增法诊断染色体22q11.2微缺失结果研究

目的 对多重连接探针扩增(multiplex ligation-dependent probe amplification,MLPA)诊断染色体22q11.2微缺失结果进行评价.方法 应用MLPA及荧光原位杂交(fluorescence in situ hybridization,FISH)两种方法分别检测了32份儿童(男16例,女16例;年龄1～13岁,平均3.6±3.1岁)血样本,其中16例为染色体22q11.2微缺失患儿组(阳性对照组),16名为体检正常儿童组(阴性对照组).采用灵敏度、特异度及Kappa分析来评估结果.结果 MLPA检测32份样本中,16例阳性对照样本均有染色体22q11.2微缺失,且缺失片段长度约3-Mb;16名对照样本中未发现22号染色体缺失.FISH证实16例22q11.2微缺失患儿均存在缺失,16名对照样本不存在缺失.因此,MLPA诊断染色体22q11.2微缺失的灵敏度及特异度高.结论 MLPA是一种快速、可靠、高通量及相对经济的诊断染色体22q11.2微缺失的有效方法,弥补了FISH技术的不足,可用于临床实验室快速诊断染色体22q11.2微缺失,具有较高的临床诊断价值.

Abstract：

Objective To evaluate multiplex ligation-dependent probe amplification (MLPA) assay detection in analysis of chromosome 22q11.2 microdeletion. Methods Between March 2008 and September 2009, thirty-two patients including 10 males and 16 females aged between years (3.6±3.1) were selected and evaluated by history, physical examination and medical records. Of these patients, sixteen patients who were previous diagnostic as 22q11.2 microdeletion were in positive control group, the other 16 healthy children were in negative control group. All the patients were detected by MLPA and fluorescence in situ hybridization (FISH) for the presence of a 22q1 1.2 microdeletion after informed consent. Diagnostic efficacy was assessed by sensitivity, specificity and Kappa analysis. Results We have applied the two assays of detection of chromosome 22q11.2 microdeletion in 32 patients. Sixteen patients in positive control group were found to have a 22q11. 2 deletion and, with the deletion size of 3-Mb. However, as expected,chromosome 22q11.2 deletion was not found in negative control group. The MLPA results were in good agreement with that by FISH. Therefore, MLPA has high sensitivity and specificity. Conclusion MLPA is a rapid, reliable, high-throughput and relatively economical alternative to FISH technology for the diagnosis of 22q11.2 microdeletion. It can provide reliable and helpful information for clinical diagnosis of 22q11.2 microdeletion syndrome.     

人类染色体22q11.2微缺失综合征发病机制的研究进展

22q11缺失综合征（22qll deletion syndrome,22qllDS）是由染色22q11．21-q11．23缺失引起的遗传性综合征，其临床表现复杂，主要包括心脏、颅面、免疫等系统异常。22qll缺失产生的机制是缺失区域内低拷贝重复序列（10w-copy-repetitives，LCR22s）之间的不对称重组。本文对其临床表现、发病机制、候选基因克隆等方面的近年进展进行了综述。     

人类染色体22q11.2微缺失综合征发病机制的研究进展

22ql1缺失综合征(22q11 deletion syndrome,22q11DS)是由染色22ql1.21-ql1.23缺失引起的遗传性综合征，其临床表现复杂，主要包括心脏、颅面、免疫等系统异常。22q11缺失产生的机制是缺失区域内低拷贝重复序列(1ow-copy-repetitives，LCR22s)之间的不对称重组。本文对其临床表现、发病机制、候选基因克隆等方面的近年进展进行了综述。     

Analyses of the associations between the genes of 22q11 deletion syndrome and schizophrenia

Schizophrenia is a severe, debilitating mental disorder characterized by profound disturbances of cognition, emotion and social functioning. The lifetime morbid risk is surprisingly uniform at slightly less than 1% across different populations and different cultures. The evidence of genetic risk factors is our strongest clue to the cause of schizophrenia. Linkage and association analyses have identified genes associated with the development of schizophrenia. However, most of the alleles or haplotypes identified thus far have only a weak association or are reported to be population specific. A deletion of 22q11.2 that causes the most common microdeletion syndrome (22q11DS) with an estimated prevalence of 1:2,500–1:4,000 live births may represent one of the greatest known genetic risk factors for schizophrenia. Schizophrenia is a late manifestation in approximately 30% of patients with 22q11.2 deletion, comparable to the risk to offspring of two parents with schizophrenia. Clinical and neuroimaging assessments indicate that 22q11DS-schizophrenia is a neurodevelopmental model of schizophrenia. Recent studies have provided evidence that haploinsufficiency of TBX1 is likely to be responsible for many of the physical features associated with the deletion. Most of the genes in the 22q11 deletion region are conserved together on mouse chromosome 16, enabling the generation of mouse models. Similarities in the cardiovascular and other phenotypes between 22q11DS patients and mouse models can provide important insights into roles of genes in neurobehavioral phenotypes. Because more than one gene in the 22q11DS region is likely to contribute to the marked risk for schizophrenia, further extensive studies are necessary. Analyses of 22q11DS will help clarify the molecular pathogenesis of schizophrenia.     

Molecular diagnosis of 22q11.2 deletion and duplication by multiplex ligation dependent probe amplification

22q11 Deletion syndrome (22q11DS) is the most common microdeletion syndrome in humans, occurring with an incidence of 1 in 4,000. In most cases the submicroscopic deletion spans 3 Mb, but there are a number of other overlapping and non-overlapping deletions that generate a similar phenotype. The majority of the 22q11.2 microdeletions can be ascertained using a standard fluorescence in situ hybridization (FISH) assay probing for TUPLE1 or N25 on 22q11.2. However, this test fails to detect deletions that are either proximal or distal to the FISH probes, and does not provide any information about the length of the deletion. In order to increase the detection rate of 22q11.2 deletion and to better characterize the size and position of such deletions we undertook a study of 22q11.2 cases using multiplex ligation dependent probe amplification (MLPA). We used MLPA to estimate the size of the 22q11.2 deletions in 51 patients positive for TUPLE1 or N25 (FISH) testing, and to investigate 12 patients with clinical features suggestive of 22q11DS and negative FISH results. MLPA analysis confirmed a microdeletion in all 51 FISH-positive samples as well as microduplications in three samples. Further, it allowed us to delineate deletions not previously detected using standard clinical FISH probes in 2 of 12 subjects with clinical features suggestive of 22q11DS. We conclude that MLPA is a cost-effective and accurate diagnostic tool for 22q11DS with a higher sensitivity than FISH alone. Additional advantages of MLPA testing in our study included determination of deletion length and detection of 22q11.2 duplications. (c) 2007 Wiley-Liss, Inc.