21号染色体上STR位点的遗传多态性研究

目的调查21号染色体上4个短串联重复序列位点：D21S11、D21S1432、D21S2054和D21S1446在西安汉族人群中的基因频率分布和法医学统计参数。方法以西安地区汉族100例无关个体为研究对象，选用唐氏综合征关键区域内及其附近4个短串联重复序列位点，应用聚合酶链反应和变性聚丙烯酰胺凝胶电泳及银染技术对其进行遗传多态性调查分析。结果100例无关个体4个位点（D21S11、D21S1432、D21S2054和D21S1446）分别检出12、8、6、8个等位基因；基因型分布均符合HardyWeinberg定律。结论21号染色体上4个短串联重复序列位点均有较高的个体识别率，在个体识别和亲权鉴定中有应用价值，对唐氏综合征的基因诊断有临床指导意义。

广东部分地区376例遗传咨询者染色体21-三体综合征分析

目的了解广东地区临床1岁以内婴幼儿的21-三体综合征的发生及分布情况。方法本文通过遗传咨询筛查,和进行G显带染色体研究,对在2004年1年内376例来自广东省各地区临床的1周岁以内的婴幼患儿进行检查。结果检出异常核型113例,总的异常率为30.05%。其中21三体95例,占总异常的84.07%,男性21三体60例,女性21三体35例,是婴儿染色体异常的主要原因。结论21三体患儿的出生给家庭和社会带来沉重的负担和许多不良影响。本文提出,整个社会都应大力提倡通过产前筛查(孕早期AFP、uE3、βhCG组合项目筛查)、产前诊断(脐血、羊水等染色体检查)及选择性人工流产的方法杜绝患儿出生。

21三体畸形儿外周血淋巴细胞中各种21号染色体非整体细胞的发生率

目的 阐述人体内各种 21号染色体非整倍体的原理和特点。方法 用 CB－ FISH法测定了 12例 21三体患者和 20例正常儿童体内各种 21号染色体非整倍体淋巴细胞的发生率。结果 在正常儿童体内， 21三体细胞率远高于 21单体细胞率，提示 21号染色体的不分离大于丢失，而在 21三体患儿体内， 21四体细胞率却显著低于二倍体细胞率，与体外观察到的 21号染色体的不分离远大于丢失的结果相反。结论 机体内存在对细胞系的选择淘汰机制。

Amplification of chromosome 21q22.3 harboring trefoil factor family genes in liver fluke related cholangiocarcinoma is associated with poor prognosis

AIM： To determine allelic imbalance on chromosomal region 21q22-qter including trefoil factor family genes （TFF） in cholangiocarcinoma （CCA） patients and analyze the correlation between allelic imbalances and clinicopathological parameters. METHODS： Quantitative PCR amplification was performed on four microsatellite markers and trefoil factor family genes （TFF1, TFF2, and TFF3） using a standard curve and SYBR Green I dye method. The relative copy number was determined by DNA copy number of tested locus to reference locus. The relative copy number was interpreted as deletion or amplification by comparison with normal reference range. Associations between allelic imbalance and clinicopathological parameters of CCA patients were evaluated by χ^2-tests. Kaplan-Meier method was used to analyze survival. RESULTS： The frequencies of amplification at D21S1890, D21S1893, and TFF3 were 32.5%, 30.0%, and 28.7%, respectively. Patients who had amplification at regions covering D21S1893, D21S1890, and TFF showed poor prognosis, whereas patients who had deletion showed favorable prognosis （mean： 51.7 wk vs 124.82 wk, P = 0.012）. Multivariate Cox regression analysis revealed that amplification of D21S1893, D21S1890 and TFF, blood vessel invasion, and staging were associated with poor prognosis. CONCLUSION： D21S1893-D21S1890 region may harbor candidate genes especially TFF and serine protease family, which might be involved in tumor invasion and metastasis contributing to poor survival. The amplification in this region may be used as a prognostic marker in the treatment of CCA patients.

Down syndrome and the molecular pathogenesis resulting from trisomy of human chromosome 21

Elizabeth Fisher and Victor collaboratively for many years on Tybulewicz have worked the Down syndrome mouse model project. Elizabeth Fisher＇s background is in molecular genetics and mouse models, with an interest in anueploidy. Victor Tybulewicz is an immunologist whose primary interest is in signal transduction from the antigen receptors of B and T cells.

Detailed Deletion Mapping of Chromosome 9p21-22 in Nasopharyngeal Carcinoma

Objective: To further refine the extent of deletion on chromosome 9p21-22 in nasopharyngeal carcinoma (NPC) and provide evidence for discovering new tumor suppressor gene. Methods: Loss of heterozygosity (LOH) on chromosome 9p21-22 was analyzed in 25 paired blood and tumor samples by using 11 high-density microsatellite polymorphic markers. Results: 17 of 25 cases (68.0%) showed LOH at one or more loci. Higher frequencies of LOH were found at four loci: D9S161 (35.0%), D9S1678 (31.5%), D9S263 (33.3%) and D9S1853 (33.3%), where 6 cases had a contiguous stretch of allelic loss. Conclusion: The minimal common region of deletion might be defined between D9S161 and D9S1853 (estimated about 2.7 cM in extent) at 9p21.1, suggesting that inactivation of one or more tumor suppressor genes located in this region may be an important step in NPC.